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%I #4 Aug 04 2021 13:53:56
%S 1,1,1,0,1,0,1,0,0,1,0,1,0,0,0,0,1,1,0,0,0,0,1,0,1,0,0,0,0,1,0,1,1,0,
%T 0,0,0,1,0,1,0,0,0,0,1,0,1,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,
%U 0,1,0,1,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,1,0,0,1,0,0
%N a(n) = 1 iff 6*n+1 and 6*n-1 are both prime numbers (0 otherwise).
%C Characteristic function of A002822. - _Georg Fischer_, Aug 04 2021
%e a(3) = 1 because 6*3-1=17 and 6*3+1=19 are both prime.
%e a(4) = 0 because 6*4-1=23 is prime and 6*4+1=25 is not prime.
%e a(20) = 0 because 6*20-1=119 and 6*20+1=121 are both not prime.
%t Table[If[And[PrimeQ[6*k - 1], PrimeQ[6*k + 1]], 1, 0], {k, 1, 110}]
%Y Cf. A000040, A002822, A100924, A100925.
%K nonn
%O 1,1
%A Joseph Biberstine (jrbibers(AT)indiana.edu), Nov 22 2004
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