A117551 Indices of Fibonacci numbers with 15 distinct prime factors.

180, 210, 276, 280, 288, 312, 320, 340, 342, 416, 464, 476, 486, 516, 558, 564, 651, 665, 676, 708, 730, 735, 752, 776, 783, 837, 848, 856, 890, 992, 999, 1030, 1034, 1038, 1065, 1068, 1071, 1095, 1125, 1130, 1192, 1212

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Blair Kelly, Fibonacci and Lucas Factorizations.

Example

F(180) = 2^4 * 3^3 * 5 * 11 * 17 * 19 * 31 * 41 * 61 * 107 * 181 * 541 * 2521 * 109441 * 10783342081 has 15 distinct prime factors, so 180 is in the sequence.

Prog

(PARI) isok(n) = (omega(fibonacci(n)) == 15) \\ Michel Marcus, Jun 28 2013

Crossrefs

Cf. A114823-A114826, A114836-A114841.

Column k=15 of A303217.

Sequence in context: A154360 A253393 A260265 * A068545 A068403 A291457

Adjacent sequences: A117548 A117549 A117550 * A117552 A117553 A117554

Keyword

hard,more,nonn

Author

Ryan Propper, Apr 26 2006

Extensions

a(32)-a(42) from Max Alekseyev, Aug 18 2013

Status

approved