A270532 - OEIS

A270532

Integers k such that A003266(p) is not divisible by p*(p+1)/2 where p is the k-th prime.

1, 2, 4, 9, 14, 19, 23, 27, 31, 38, 39, 48, 49, 61, 73, 76, 86, 90, 91, 93, 96, 99, 101, 107, 111, 117, 118, 124, 129, 138, 143, 144, 150, 153, 154, 155, 161, 166, 179, 188, 192, 195, 208, 213, 217, 219, 224, 229, 236, 243, 247, 250, 253, 258, 261, 262, 269, 272, 276, 277, 283, 285, 292, 300

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

See A000057 to corresponding prime numbers. In other words, this sequence is an indirect way to generate primes dividing all Fibonacci sequences.

LINKS

Michel Marcus, Table of n, a(n) for n = 1..1000

PROG

(PARI) f(n) = prod(k=1, n, fibonacci(k)); \\ A003266

isok(n) = (lift(Mod(f(prime(n)), (prime(n)*(prime(n)+1)/2))) != 0);

(PARI) isok(n) = my(p=prime(n), m=p*(p+1)/2); prod(k=1, p, Mod(fibonacci(k), m)); \\ Michel Marcus, May 14 2021

CROSSREFS