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%I #18 Apr 14 2013 14:34:48
%S 0,0,0,0,0,1,1,2,1,2,1,2,3,2,1,4,2,2,2,3,2,2,2,2,4,4,1,4,4,3,3,3,3,3,
%T 3,4,4,5,0,5,7,3,3,6,3,5,3,5,4,6,2,3,6,2,5,6,3,5,5,4,6,6,3,5,7,3,4,8,
%U 3,5,5,3,4,7,3,6,6,5,5,8,4,3,8,4,5,8,1
%N Number of ways to express 2n+1 as p+4q with p, q primes.
%C This is related to the conjecture given in A219252.
%C a(38) = 0 because A219252(38) = 0.
%H Michel Lagneau, <a href="/A219254/b219254.txt">Table of n, a(n) for n = 0..10000</a>
%e a(15) = 4 because 31 = 23 + 4*2 = 19 + 4*3 = 11 + 4*5 = 3 + 4*7 with 4 decompositions.
%t a[n_] := (ways = 0; Do[p = 2k + 1; q = (n-k)/2; If[PrimeQ[p] && PrimeQ[q], ways++], {k, 1, n}]; ways); Table[a[n], {n, 0, 91}]
%Y Cf. A046927, A219252.
%K nonn
%O 0,8
%A _Michel Lagneau_, Apr 11 2013
%E Name corrected by _Zak Seidov_, Apr 14 2013
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