A263169 Smallest positive k such that 78557^k + 2^n is prime, or 0 if no such value exists.

0, 33, 2, 0, 76

Offset

0,2

Comments

{0, 2, 3} is the set of all noncomposite numbers that belong to this sequence.

The sequence continues: a(5) = ?, a(6) = ?, 87, 12, 0, 0, 3, a(12) = ?.

Links

Table of n, a(n) for n=0..4.

Prog

(Magma) lst:=[]; for n in [1..4] do if not n mod 6 eq 3 then k:=2; while not IsPrime(78557^k+2^n) do k+:=1; end while; Append(~lst, k); else Append(~lst, 0); end if; end for; [0] cat lst;

Crossrefs

Cf. A076336.

Sequence in context: A218116 A279364 A308408 * A034060 A032445 A333128

Adjacent sequences: A263166 A263167 A263168 * A263170 A263171 A263172

Keyword

nonn,more

Author

Arkadiusz Wesolowski, Oct 11 2015

Status

approved