cp's OEIS Frontend

A156706 For all numbers k(n) congruent to +1 or -1 (mod 6) starting with k(n) = {5,7,11,13,...}, a(k(n)) is the congruence (mod 6) if k(n) is prime and 0 if k(n) is composite.

%I A156706 #8 Nov 24 2019 23:39:26
%S A156706 -1,1,-1,1,-1,1,-1,0,-1,1,0,1,-1,1,-1,0,-1,0,-1,1,0,1,-1,1,0,1,-1,0,
%T A156706 -1,0,0,1,-1,1,-1,1,-1,0,0,0,0,1,-1,0,-1,1,0,0,-1,1,0,1,0,1,-1,0,-1,0,
%U A156706 -1,1,0,0,-1,1,-1,1,0,0,0,1,0,0,0,1,-1,1,-1,0,-1,1,0,0,-1,0,-1,0,-1,0,-1,1,0
%N A156706 For all numbers k(n) congruent to +1 or -1 (mod 6) starting with k(n) = {5,7,11,13,...}, a(k(n)) is the congruence (mod 6) if k(n) is prime and 0 if k(n) is composite.
%C A156706 Expression for k(n): k(n) = 6*ceiling(n/2) + (-1)^n, so the parity of n gives us the congruence (mod 6) of k(n). - _Daniel Forgues_, Mar 01 2009
%H A156706 Daniel Forgues, <a href="/A156706/b156706.txt">Table of n, a(n) for n = 1..33332</a>
%Y A156706 Cf. A075743.
%Y A156706 The absolute values of this sequence give A075743. The partial sums of this sequence give A156709.
%K A156706 sign
%O A156706 1,1
%A A156706 _Daniel Forgues_, Feb 13 2009, Feb 14 2009