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A026053 (d(n)-r(n))/5, where d = A008778 and r is the periodic sequence with fundamental period (0,3,1,0,1). 1
1, 2, 5, 9, 14, 21, 29, 40, 53, 68, 86, 106, 130, 157, 187, 221, 258, 300, 346, 396, 451, 510, 575, 645, 720, 801, 887, 980, 1079, 1184, 1296, 1414, 1540, 1673, 1813, 1961, 2116, 2280, 2452, 2632, 2821, 3018, 3225, 3441, 3666, 3901, 4145, 4400, 4665, 4940, 5226, 5522, 5830, 6149, 6479, 6821 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..57.

FORMULA

a(n)=(n + 2)*(n^2 + 10*n + 15)/30 - 1/5*(1 + ( - 1/2 + 3/10*5^(1/2))*cos(2*n*Pi/5) + (1/5*2^(1/2)*(5 + 5^(1/2))^(1/2) + 1/10*2^(1/2)*(5 - 5^(1/2))^(1/2))*sin(2*n*Pi/5) + ( - 1/2 - 3/10*5^(1/2))*cos(4*n*Pi/5) + ( - 1/10*2^(1/2)*(5 + 5^(1/2))^(1/2) + 1/5*2^(1/2)*(5 - 5^(1/2))^(1/2))*sin(4*n*Pi/5)) [From Richard Choulet, Dec 14 2008]

a(n)= 3*a(n-1) -3*a(n-2) +a(n-3) +a(n-5) -3*a(n-6) +3*a(n-7) -a(n-8). G.f.: -x^2*(-1+x-2*x^2+x^3)/( (x^4+x^3+x^2+x+1) * (x-1)^4 ). [From R. J. Mathar, Oct 05 2009]

CROSSREFS

A152892 [From Richard Choulet, Dec 14 2008]

Sequence in context: A191123 A152888 A139423 * A276031 A011905 A306674

Adjacent sequences:  A026050 A026051 A026052 * A026054 A026055 A026056

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified May 26 17:16 EDT 2022. Contains 354092 sequences. (Running on oeis4.)