A274003 Primitive terms (not equal twice a smaller term) of A178751: moduli n such that x^y == -1 (mod n) only for x = -1 (mod n).

2, 3, 15, 20, 51, 68, 255, 340, 771, 1028, 3855, 5140, 13107, 17476, 65535, 87380, 196611, 262148, 983055

Offset: 1

Author

M. F. Hasler, Jun 06 2016

Keywords

• nonn
• hard
• more

Comments

See A178751 for further information. In particular, A038192 is the subsequence of odd terms.

Crossrefs

Cf. A038192, A178751.

Programs

PARI

is_A274003(n)={is_A178751(n) && (bittest(n,0) || !is_A178751(n\2))}

PARI

select( n -> bittest(n,0) || !setsearch(A178751,n\2), A178751) \\ assuming the vector A178751 holds enough terms of that sequence.