OFFSET
1,1
LINKS
Michel Marcus, Table of n, a(n) for n = 1..10000
EXAMPLE
a(9)=0 because 9*k^2-1 is never a prime: (3k-1)*(3k+1).
PROG
(PARI) a(n) = if (issquare(n) && (n>=9), 0, my(k=1); while (!isprime(n*k^2 - 1), k++); k); \\ Michel Marcus, Aug 20 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Nov 12 2013
STATUS
approved