A026051 a(n) = (d(n)-r(n))/5, where d = A026049 and r is the periodic sequence with fundamental period (4,1,4,0,1).
23, 31, 40, 53, 68, 86, 109, 135, 167, 203, 244, 292, 345, 406, 473, 547, 630, 720, 820, 928, 1045, 1173, 1310, 1459, 1618, 1788, 1971, 2165, 2373, 2593, 2826, 3074, 3335, 3612, 3903, 4209, 4532, 4870, 5226, 5598, 5987, 6395, 6820, 7265, 7728, 8210, 8713, 9235, 9779, 10343, 10928, 11536
Offset: 7
Keywords
Crossrefs
A152890 [From Richard Choulet, Dec 14 2008]
Formula
a(n)=(n + 7)*(2*n^2 + 13*n + 102)/30 - 1/5*(2 + ( - 1/5*5^(1/2) + 1)*cos(2*n*Pi/5) + (2/5*2^(1/2)*(5 - 5^(1/2))^(1/2))*sin(2*n*Pi/5) + (1/5*5^(1/2) + 1)*cos(4*n*Pi/5) + ( - 2/5*2^(1/2)*(5 + 5^(1/2))^(1/2))*sin(4*n*Pi/5)) [From Richard Choulet, Dec 14 2008]
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