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%I #11 Dec 16 2017 05:31:55
%S 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,0,1,1,1,1,1,1,0,1,1,0,
%T 1,0,1,1,1,1,0,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,0,1,1,1,1,1,1,1,1,1,1,1,
%U 0,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,0,1,0,0,1,1,0,1,1,1,1,0,1,1,1,1,1,1,0,1
%N A (negated) characteristic function of twin composite odd numbers.
%C a(n) = 0 if n is a member of A060461, otherwise a(n) = 1.
%H Antti Karttunen, <a href="/A161996/b161996.txt">Table of n, a(n) for n = 1..37317</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%t If[AllTrue[6#+{1,-1},CompositeQ],0,1]&/@Range[300] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Feb 15 2015 *)
%o (PARI) A161996(n) = (isprime((6*n)-1)||isprime((6*n)+1)); \\ _Antti Karttunen_, Dec 15 2017
%Y Cf. A060461, A100923.
%K nonn,easy
%O 1,1
%A _Pierre CAMI_, Jun 24 2009
%E Definition rephrased by _R. J. Mathar_, Aug 14 2009