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Search: id:A140150
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| A140150 |
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a(1)=1, a(n)=a(n-1)+n^2 if n odd, a(n)=a(n-1)+ n^4 if n is even. |
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+0
2
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| 1, 17, 26, 282, 307, 1603, 1652, 5748, 5829, 15829, 15950, 36686, 36855, 75271, 75496, 141032, 141321, 246297, 246658, 406658, 407099, 641355, 641884, 973660, 974285, 1431261, 1431990, 2046646, 2047487, 2857487, 2858448, 3907024, 3908113
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n)=a(n-1)+{[1-(-1)^n]/2}*n^2+{[1+(-1)^n]/2}*n^4, with a(1)=1 a(n)= -(1/2)*(-1)^n*n+(1/2)*(-1)^n*n^3+(1/3)*n^3-(1/4)*(-1)^n*n^2+(1/4)*n^2+(1/15)*n+(1/10)*n^5+(1/4) *(-1)^n*n^4+(1/4)*n^4, with n>=1 - Paolo P. Lava (ppl(AT)spl.at), Jun 06 2008
G.f.: x*(1+16*x+4*x^2+176*x^3-10*x^4+176*x^5+4*x^6+16*x^7+x^8)/((1+x)^5*(x-1)^6). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 22 2009]
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MATHEMATICA
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a = {}; r = 2; s = 4; Do[k = 0; Do[k = k + (Sin[Pi m/2]^2) m^r + (Cos[Pi m/2]^2) m^s, {m, 1, n}]; AppendTo[a, k], {n, 1, 100}]; a (*Artur Jasinski*)
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CROSSREFS
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Cf. A000027, A000217, A000330, A000537, A000538, A000539, A136047, A140113.
Adjacent sequences: A140147 A140148 A140149 this_sequence A140151 A140152 A140153
Sequence in context: A031204 A085051 A154277 this_sequence A166658 A033702 A000797
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KEYWORD
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nonn
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AUTHOR
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Jasinski Artur (grafix(AT)csl.pl), May 12 2008
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