A367970 - OEIS

A367970

Least k such that 5*n*k+1 is a prime.

2, 1, 2, 2, 4, 1, 2, 1, 4, 2, 6, 1, 2, 1, 2, 3, 12, 2, 2, 1, 2, 3, 4, 2, 2, 1, 2, 2, 10, 1, 2, 4, 2, 6, 4, 1, 8, 1, 6, 2, 4, 1, 2, 3, 8, 2, 4, 1, 2, 1, 4, 2, 4, 1, 12, 1, 2, 5, 4, 2, 6, 1, 2, 2, 4, 1, 6, 3, 2, 2, 6, 5, 18, 4, 2, 2, 6, 3, 6, 1, 2, 2, 28, 1, 6

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

OFFSET

1,1

LINKS

Robert Price, Table of n, a(n) for n = 1..5000

MATHEMATICA

A367970 = {};

Do[k=1; While[!PrimeQ[5 n k+1], k++]; AppendTo[A367970 , k], {n, 85}];

A367970

PROG

(PARI) a(n) = my(k=1); while (!isprime(5*n*k+1), k++); k; \\ Michel Marcus, Dec 17 2023

CROSSREFS