A178187 Numerators of sum (1/3)^((k^2+3k)/2) from k=1 to n.
1, 28, 2269, 551368, 401947273, 879058686052, 5767504039187173, 113521782003321126160, 6703347705514109178621841, 1187477935988707898665323267628, 631074461779774914374598062671491949
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..60
Programs
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Mathematica
aa = {}; m = 1/3; sum = 0; Do[sum = sum + m^((n + 3) n/2); AppendTo[aa, Numerator[sum]], {n, 1, 20}]; aa (*Artur Jasinski*) Accumulate[Table[(1/3)^((k^2+3k)/2),{k,20}]]//Numerator (* Harvey P. Dale, May 29 2020 *) -
PARI
a(n) = numerator(sum(k=1, n, (1/3)^((k^2+3*k)/2))); \\ Michel Marcus, Sep 09 2013
Comments