OFFSET
1,1
PROG
(PARI) a8(n) = my(k=1); while(!isprime(k*n*2^n+1), k+=2); k;
a9(n) = my(k=1); while(!isprime(k*n*2^n-1), k+=2); k;
isok(n) = a8(n) == a9(n); \\ Michel Marcus, Sep 15 2019
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Pierre CAMI, Apr 24 2015
STATUS
approved