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Search: id:A140156
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| A140156 |
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a(1)=1, a(n)=a(n-1)+n^3 if n odd, a(n)=a(n-1)+ n^5 if n is even. |
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+0
2
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| 1, 33, 60, 1084, 1209, 8985, 9328, 42096, 42825, 142825, 144156, 392988, 395185, 933009, 936384, 1984960, 1989873, 3879441, 3886300, 7086300, 7095561, 12249193, 12261360, 20223984, 20239609, 32120985, 32140668, 49351036, 49375425
(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^3+{[1+(-1)^n]/2}*n^5, with a(1)=1 a(n)= (-3/16)+(3/16)*(-1)^n-(1/4)*(-1)^n*n^3+(1/4)*n^3-(-1)^n*n^2+(1/12)*n^2+(1/12)*n^6+(1/4)*(-1)^n *n^5+(1/4)*n^5+(5/8)*(-1)^n*n^4+(1/3)*n^4, with n>=1 - Paolo P. Lava (ppl(AT)spl.at), Jun 06 2008
G.f.: -x*(1+32*x+21*x^2+832*x^3-22*x^4+2112*x^5-22*x^6+832*x^7+21*x^8+32*x^9+x^ 10)/((1+x)^6*(x-1)^7). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 22 2009]
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MATHEMATICA
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a = {}; r = 3; s = 5; 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.
Sequence in context: A043203 A043983 A080673 this_sequence A154600 A100593 A115160
Adjacent sequences: A140153 A140154 A140155 this_sequence A140157 A140158 A140159
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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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