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A026062
a(n) = (d(n)-r(n))/5, where d = A026060 and r is the periodic sequence with fundamental period (0,0,1,4,0).
1
9, 16, 25, 36, 51, 68, 88, 111, 137, 168, 202, 240, 282, 328, 380, 436, 497, 563, 634, 712, 795, 884, 979, 1080, 1189, 1304, 1426, 1555, 1691, 1836, 1988, 2148, 2316, 2492, 2678, 2872, 3075, 3287, 3508, 3740, 3981, 4232, 4493, 4764, 5047, 5340, 5644, 5959, 6285, 6624, 6974, 7336, 7710, 8096
OFFSET
5,1
FORMULA
a(n)=(n + 5)*(n^2 + 25*n + 54)/30 - 1/5*(1 + ( - 1/2 - 1/2*5^(1/2))*cos(2*n*Pi/5) + ( - 3/10*2^(1/2)*(5 - 5^(1/2))^(1/2))*sin(2*n*Pi/5) + ( - 1/2 + 1/2*5^(1/2))*cos(4*n*Pi/5) + (3/10*2^(1/2)*(5 + 5^(1/2))^(1/2))*sin(4*n*Pi/5)) - Richard Choulet, Dec 14 2008
G.f. x^5*( 9-11*x+4*x^2+2*x^4-11*x^5+12*x^6-4*x^7 ) / ( (x^4+x^3+x^2+x+1)*(x-1)^4 ). - R. J. Mathar, Jun 23 2013
CROSSREFS
Cf. A152894.
Sequence in context: A339859 A076093 A085585 * A108945 A177430 A256705
KEYWORD
nonn,easy
STATUS
approved