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A026055
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a(n) = (d(n)-r(n))/2, where d = A026054 and r is the periodic sequence with fundamental period (1,0,0,0).
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0
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6, 14, 25, 40, 59, 84, 114, 150, 192, 242, 299, 364, 437, 520, 612, 714, 826, 950, 1085, 1232, 1391, 1564, 1750, 1950, 2164, 2394, 2639, 2900, 3177, 3472, 3784, 4114, 4462, 4830, 5217, 5624, 6051, 6500, 6970, 7462, 7976, 8514, 9075, 9660, 10269, 10904, 11564, 12250, 12962, 13702, 14469, 15264
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OFFSET
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3,1
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LINKS
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FORMULA
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a(n) = - 0.125 - 0.125*( - 1)^n - 0.25*cos(n*Pi/2) + (n + 2)*(n + 3)*(n + 13)/12 [From Richard Choulet, Dec 13 2008]
a(n) = (n + 2)*(n + 3)*(n + 13)/12 - 0.125 - 0.125*( - 1)^n - 0.25*cos(n*Pi/2) [From Richard Choulet, Dec 13 2008]
G.f.: x^3*( 6-4*x+x^2+x^3+6*x^5-2*x^6-6*x^4 ) / ( (1+x)*(x^2+1)*(x-1)^4 ). - R. J. Mathar, Jun 22 2013
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MATHEMATICA
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LinearRecurrence[{3, -3, 1, 1, -3, 3, -1}, {6, 14, 25, 40, 59, 84, 114}, 60] (* Harvey P. Dale, Mar 27 2013 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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