A114838 Indices of Fibonacci numbers with 7 distinct prime factors.
70, 81, 104, 105, 136, 148, 152, 164, 182, 186, 195, 207, 212, 244, 246, 254, 259, 289, 291, 292, 298, 305, 319, 326, 332, 344, 365, 367, 403, 404, 423, 445, 447, 451, 458, 478, 489, 511, 517, 519, 526, 533, 537, 543, 554, 565, 566, 597, 605, 679, 681, 685, 698, 699, 701, 721, 723, 725, 737, 745, 746, 749, 753, 758, 766, 767, 785, 813, 817, 831, 842, 871, 879, 901, 905, 914, 955, 967, 973, 985, 998, 1006, 1007, 1009, 1043, 1046, 1051, 1133, 1139, 1159, 1167, 1174, 1175, 1177, 1191, 1199, 1207, 1219
Offset: 1
Keywords
Examples
a(1)=70 because the 70th Fibonacci number consists of 7 distinct prime factors (i.e., 190392490709135 = 5 x 11 x 13 x 29 x 71 x 911 x 141961).
Links
- Amiram Eldar, Table of n, a(n) for n = 1..112
- Blair Kelly, Fibonacci and Lucas Factorizations.
Programs
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Mathematica
Select[Range[1220],PrimeNu[Fibonacci[#]]==7&] (* Harvey P. Dale, Sep 18 2020 *)
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PARI
n=1;while(n<310,if(omega(fibonacci(n))==7,print1(n,", "));n++)
Extensions
More terms from Ryan Propper, Apr 26 2006
a(53)-a(98) from Max Alekseyev, Aug 18 2013