A106671 a(n) = ( prime(n + 2) * prime(n) - prime(n + 1)^2 ) modulo 3.

1, 2, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1

Offset: 1

Author

Roger L. Bagula, May 13 2005

Keywords

• nonn
• less

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A010872, A056221.

Programs

Mathematica

a = Table[Mod[Prime[n + 2]*Prime[n] - Prime[n + 1]^2, 3], {n, 1, 200}]
Mod[#[[3]]#[[1]]-#[[2]]^2,3]&/@Partition[Prime[Range[110]],3,1] (* Harvey P. Dale, Oct 03 2015 *)

PARI

a(n) = (prime(n + 2)*prime(n) - prime(n + 1)^2) % 3; \\ Michel Marcus, Apr 21 2017

Formula

a(n) = A056221(n) mod 3 = A010872(A056221(n)). - Michel Marcus, Apr 21 2017