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a(n) = ( prime(n + 2) * prime(n) - prime(n + 1)^2 ) modulo 3.
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%I #12 Apr 21 2017 15:55:08

%S 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,

%T 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,

%U 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

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

%H G. C. Greubel, <a href="/A106671/b106671.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A056221(n) mod 3 = A010872(A056221(n)). - _Michel Marcus_, Apr 21 2017

%t a = Table[Mod[Prime[n + 2]*Prime[n] - Prime[n + 1]^2, 3], {n, 1, 200}]

%t Mod[#[[3]]#[[1]]-#[[2]]^2,3]&/@Partition[Prime[Range[110]],3,1] (* _Harvey P. Dale_, Oct 03 2015 *)

%o (PARI) a(n) = (prime(n + 2)*prime(n) - prime(n + 1)^2) % 3; \\ _Michel Marcus_, Apr 21 2017

%Y Cf. A010872, A056221.

%K nonn,less

%O 1,2

%A _Roger L. Bagula_, May 13 2005