A366951 a(n) = 2*(p_n - 1)/A060305(n) iff p_n == +/- 1 (mod 5), 2*(p_n + 1)/A060305(n) iff p_n == +/- 2 (mod 5), 0 iff p_n = 5.

2, 1, 0, 1, 2, 1, 1, 2, 1, 4, 2, 1, 2, 1, 3, 1, 2, 2, 1, 2, 1, 2, 1, 4, 1, 4, 1, 3, 2, 3, 1, 2, 1, 6, 2, 6, 1, 1, 1, 1, 2, 4, 2, 1, 1, 18, 10, 1, 1, 4, 9, 2, 2, 2, 1, 3, 2, 2, 1, 10, 1, 1, 7, 2, 1, 1, 6, 1, 3, 4, 3, 2, 1, 1, 2, 1, 2, 1, 4, 2, 2, 10, 2, 1, 2, 1

Offset: 1

Author

A.H.M. Smeets, Oct 29 2023

Keywords

• nonn

Crossrefs

Cf. A000040, A003147, A060305, A047650, A047652, A071774, A124096, A124253, A296240, A308784 - A308794.

Formula

a(n) == 0 (mod 2) for prime(n) == +/- 1 (mod 5) and n > 2.

a(n) == 1 (mod 2) for Prime(n) == +/- 2 (mod 5) and n > 2.

a(n) = 1 iff prime(n) in A071774.

a(n) = 2 iff prime(n) in ({2} union A003147)/{5}.

a(n) = 3 iff prime(n) in A308784.

a(n) = 4 iff prime(n) in A308787.

a(n) = 6 iff prime(n) in A308788.

a(n) = 7 iff prime(n) in A308785.

a(n) = 8 iff prime(n) in A308789.

a(n) = 9 iff prime(n) in A308786.

a(n) = 10 iff prime(n) in A308790.

a(n) = 12 iff prime(n) in A308791.

a(n) = 14 iff prime(n) in A308792.

a(n) = 16 iff prime(n) in A308793.

a(n) = 18 iff prime(n) in A308794.

a(n) = A296240(n) iff prime(n) == +/- 2 (mod 5) and n > 3.

a(n) = 2*A296240(n) iff prime(n) == +/- 1 (mod 5) and n > 3.

a(n) in {2^k: k > 1} iff prime(n) in {A047650}.

a(n) == 3 (mod 6) iff prime(n) in {A124096}.

a(n) == 6 (mod 12) iff prime(n) in {A046652}.

a(n) == 0 (mod 14) iff prime(n) in {A125252}.