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A171691 Number of unordered partitions {k1, k2} of n such that k1 and k2 are nonnegative nonprimes A141468.

%I A171691 #6 Jan 05 2020 16:32:55
%S A171691 1,1,0,1,1,1,1,2,2,3,1,3,2,3,3,5,2,5,3,5,4,6,3,7,5,7,5,8,5,9,6,8,7,10,
%T A171691 7,12,7,9,9,12,8,13,9,12,10,13,9,15,11,15,11,15,11,17,13,16,13,17,13,
%U A171691 20,14,16,15,20,15,22,15,18,17,22,16,23,17,21,18,23,18,26,18,23
%N A171691 Number of unordered partitions {k1, k2} of n such that k1 and k2 are nonnegative nonprimes A141468.
%H A171691 Andrew Howroyd, <a href="/A171691/b171691.txt">Table of n, a(n) for n = 1..10000</a>
%e A171691 a(1) = 1 because 1 = 0 + 1.
%e A171691 a(2) = 1 because 2 = 1 + 1.
%e A171691 a(3) = 0.
%e A171691 a(4) = 1 because 4 = 0 + 4.
%e A171691 a(5) = 1 because 5 = 1 + 4.
%e A171691 a(6) = 1 because 6 = 0 + 6.
%e A171691 a(7) = 1 because 7 = 1 + 6.
%e A171691 a(8) = 2 because 8 = 0 + 8 = 4 + 4.
%o A171691 (PARI) a(n)={sum(i=0, n\2, (i<2 || !isprime(i)) && !isprime(n-i))} \\ _Andrew Howroyd_, Jan 05 2020
%Y A171691 Cf. A062610, A141468, A224708.
%K A171691 nonn
%O A171691 1,8
%A A171691 _Juri-Stepan Gerasimov_, Dec 15 2009
%E A171691 Name clarified and terms a(55) and beyond from _Andrew Howroyd_, Jan 05 2020