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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).
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
7,1
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]
CROSSREFS
A152890 [From Richard Choulet, Dec 14 2008]
Sequence in context: A126719 A110677 A169640 * A141818 A060328 A034962
KEYWORD
nonn
STATUS
approved