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Search: id:A140148
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| A140148 |
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a(1)=1, a(n)=a(n-1)+n^2 if n odd, a(n)=a(n-1)+ n^0 if n is even. |
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+0
2
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| 1, 2, 11, 12, 37, 38, 87, 88, 169, 170, 291, 292, 461, 462, 687, 688, 977, 978, 1339, 1340, 1781, 1782, 2311, 2312, 2937, 2938, 3667, 3668, 4509, 4510, 5471, 5472, 6561, 6562, 7787, 7788, 9157, 9158, 10679, 10680, 12361, 12362, 14211, 14212, 16237
(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}, with a(1)=1 a(n)=(-1/4)-(1/4)*(-1)^n*n+(1/4)*(-1)^n+(1/6)*n^3-(1/4)*(-1)^n*n^2+(1/4)*n^2+(7/12)*n , with n>=1 - Paolo P. Lava (ppl(AT)spl.at), Jun 06 2008
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MATHEMATICA
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a = {}; r = 2; s = 0; 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: A140145 A140146 A140147 this_sequence A140149 A140150 A140151
Sequence in context: A136996 A113720 A034118 this_sequence A117547 A037091 A127303
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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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