The Fibonacci numbers

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The Fibonacci series

is formed by adding the latest two numbers to get the next one, starting from 0 and 1:
 
  0 1 --the series starts like this.
  0+1=1 so the series is now 
  0 1 1
    1+1=2 so the series continues...
  0 1 1 2 and the next term is
      1+2=3 so we now have
  0 1 1 2 3  and it continues as follows ...
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, ...

The (recurrence) formula for these Fibonacci numbers is:

F(0)=0, F(1)=1, F(n)=F(n-1)+F(n-2) for n>1.
and an explicit formula for F(n) just in terms of n (not previous terms) is given on a later page.

The first 100 Fibonacci numbers, completely factorised

If a number has no factors except 1 and itself, then it is called a prime number.
The factorizations here are produced by Maple with the command
with(combinat);
seq(lprint(n,`:`,fibonacci(n),`=`,ifactor(fibonacci(n))),n=1..100);
and then reformatted slightly:
  

The first 100 Fibonacci numbers

n   F(n)=factorization

1 : 1 = 1
2 : 1 = 1
3 : 2 = 2  Prime
4 : 3 = 3  Prime
5 : 5 = 5  Prime
6 : 8 = 23
7 : 13 = 13  Prime
8 : 21 = 3 x 7
9 : 34 = 2 x 17
10 : 55 = 5 x 11
11 : 89 = 89  Prime
12 : 144 = 24 x 32
13 : 233 = 233  Prime
14 : 377 = 13 x 29
15 : 610 = 2 x 5 x 61
16 : 987 = 3 x 7 x 47
17 : 1597 = 1597  Prime
18 : 2584 = 23 x 17 x 19
19 : 4181 = 37 x 113
20 : 6765 = 3 x 5 x 11 x 41
21 : 10946 = 2 x 13 x 421
22 : 17711 = 89 x 199
23 : 28657 = 28657  Prime
24 : 46368 = 25 x 32 x 7 x 23
25 : 75025 = 52 x 3001
26 : 121393 = 233 x 521
27 : 196418 = 2 x 17 x 53 x 109
28 : 317811 = 3 x 13 x 29 x 281
29 : 514229 = 514229  Prime
30 : 832040 = 23 x 5 x 11 x 31 x 61
31 : 1346269 = 557 x 2417
32 : 2178309 = 3 x 7 x 47 x 2207
33 : 3524578 = 2 x 89 x 19801
34 : 5702887 = 1597 x 3571
35 : 9227465 = 5 x 13 x 141961
36 : 14930352 = 24 x 33 x 17 x 19 x 107
37 : 24157817 = 73 x 149 x 2221
38 : 39088169 = 37 x 113 x 9349
39 : 63245986 = 2 x 233 x 135721
40 : 102334155 = 3 x 5 x 7 x 11 x 41 x 2161
41 : 165580141 = 59369 x 2789
42 : 267914296 = 23 x 13 x 29 x 211 x 421
43 : 433494437 = 433494437  Prime
44 : 701408733 = 3 x 43 x 89 x 199 x 307
45 : 1134903170 = 2 x 5 x 17 x 61 x 109441
46 : 1836311903 = 139 x 461 x 28657
47 : 2971215073 = 2971215073  Prime
48 : 4807526976 = 26 x 32 x 7 x 23 x 47 x 1103
49 : 7778742049 = 13 x 97 x 6168709
50 : 12586269025 = 52 x 11 x 101 x 151 x 3001
51 : 20365011074 = 2 x 1597 x 6376021
52 : 32951280099 = 3 x 233 x 521 x 90481
53 : 53316291173 = 953 x 55945741
54 : 86267571272 = 23 x 17 x 19 x 53 x 109 x 5779
55 : 139583862445 = 5 x 89 x 661 x 474541
56 : 225851433717 = 3 x 72 x 13 x 29 x 281 x 14503
57 : 365435296162 = 2 x 37 x 113 x 797 x 54833
58 : 591286729879 = 59 x 514229 x 19489
59 : 956722026041 = 353 x 2710260697
60 : 1548008755920 = 24 x 32 x 5 x 11 x 31 x 41 x 61 x 2521
61 : 2504730781961 = 555003497 x 4513
62 : 4052739537881 = 557 x 3010349 x 2417
63 : 6557470319842 = 2 x 13 x 17 x 421 x 35239681
64 : 10610209857723 = 3 x 7 x 47 x 1087 x 2207 x 4481
65 : 17167680177565 = 5 x 233 x 14736206161
66 : 27777890035288 = 23 x 89 x 199 x 19801 x 9901
67 : 44945570212853 = 269 x 1429913 x 116849
68 : 72723460248141 = 3 x 67 x 1597 x 63443 x 3571
69 : 117669030460994 = 2 x 137 x 829 x 18077 x 28657
70 : 190392490709135 = 5 x 11 x 13 x 29 x 71 x 911 x 141961
71 : 308061521170129 = 46165371073 x 6673
72 : 498454011879264 = 25 x 33 x 7 x 17 x 19 x 23 x 107 x 103681
73 : 806515533049393 = 86020717 x 9375829
74 : 1304969544928657 = 73 x 149 x 54018521 x 2221
75 : 2111485077978050 = 2 x 52 x 61 x 230686501 x 3001
76 : 3416454622906707 = 3 x 37 x 113 x 29134601 x 9349
77 : 5527939700884757 = 13 x 89 x 4832521 x 988681
78 : 8944394323791464 = 23 x 79 x 233 x 521 x 859 x 135721
79 : 14472334024676221 = 157 x 92180471494753
80 : 23416728348467685 = 3 x 5 x 7 x 11 x 41 x 47 x 1601 x 3041 x 2161
81 : 37889062373143906 = 2 x 17 x 53 x 109 x 4373 x 19441 x 2269
82 : 61305790721611591 = 370248451 x 59369 x 2789
83 : 99194853094755497 = 99194853094755497  Prime
84 : 160500643816367088 = 24 x 32 x 13 x 29 x 83 x 211 x 281 x 421 x 1427
85 : 259695496911122585 = 5 x 1597 x 3415914041 x 9521
86 : 420196140727489673 = 433494437 x 6709 x 144481
87 : 679891637638612258 = 2 x 173 x 3821263937 x 514229
88 : 1100087778366101931 = 3 x 7 x 43 x 89 x 199 x 263 x 307 x 881 x 967
89 : 1779979416004714189 = 1069 x 1665088321800481
90 : 2880067194370816120 = 23 x 5 x 11 x 17 x 19 x 31 x 61 x 181 x 541 x 109441
91 : 4660046610375530309 = 132 x 233 x 159607993 x 741469
92 : 7540113804746346429 = 3 x 139 x 461 x 275449 x 28657 x 4969
93 : 12200160415121876738 = 2 x 557 x 4531100550901 x 2417
94 : 19740274219868223167 = 6643838879 x 2971215073
95 : 31940434634990099905 = 5 x 37 x 113 x 761 x 67735001 x 29641   
96 : 51680708854858323072 = 27 x 32 x 7 x 23 x 47 x 769 x 1103 x 3167 x 2207  
97 : 83621143489848422977 = 193 x 389 x 3084989 x 361040209
98 : 135301852344706746049 = 13 x 29 x 97 x 599786069 x 6168709
99 : 218922995834555169026 = 2 x 17 x 89 x 197 x 18546805133 x 19801
100: 354224848179261915075 = 3 x 52 x 11 x 41 x 101 x 151 x 401 x 570601 x 3001

[There is a complete list of all Fibonacci numbers and their factors up to the 1000-th Fibonacci and 1000-th Lucas numbers and partial results beyond that on Blair Kelly's site.]
© 1995-2001 Dr Ron Knott    R.Knott@surrey.ac.uk     updated: 24 January 2000