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Search: id:A140159
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| A140159 |
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a(1)=1, a(n)=a(n-1)+n^4 if n odd, a(n)=a(n-1)+ n^2 if n is even. |
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+0
2
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| 1, 5, 86, 102, 727, 763, 3164, 3228, 9789, 9889, 24530, 24674, 53235, 53431, 104056, 104312, 187833, 188157, 318478, 318878, 513359, 513843, 793684, 794260, 1184885, 1185561, 1717002, 1717786, 2425067, 2425967, 3349488, 3350512, 4536433
(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^4+{[1+(-1)^n]/2}*n^2, with a(1)=1 a(n)= 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
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MATHEMATICA
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a = {}; r = 4; s = 2; 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: A140156 A140157 A140158 this_sequence A140160 A140161 A140162
Sequence in context: A012815 A113107 A018925 this_sequence A073862 A069948 A054954
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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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