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Search: id:A140146
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| A140146 |
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a(1)=1, a(n)=a(n-1)+n^1 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, 20, 276, 281, 1577, 1584, 5680, 5689, 15689, 15700, 36436, 36449, 74865, 74880, 140416, 140433, 245409, 245428, 405428, 405449, 639705, 639728, 971504, 971529, 1428505, 1428532, 2043188, 2043217, 2853217, 2853248, 3901824, 3901857
(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+{[1+(-1)^n]/2}*n^4, with a(1)=1 a(n)=(1/8)-(1/2)*(-1)^n*n-(1/8)*(-1)^n+(1/2)*(-1)^n*n^3+(1/6)*n^3+(1/4)*n^2+(7/30)*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
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MATHEMATICA
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a = {}; r = 1; 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.
Sequence in context: A146169 A045020 A069961 this_sequence A039502 A039505 A128546
Adjacent sequences: A140143 A140144 A140145 this_sequence A140147 A140148 A140149
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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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