

A178191


Numerators of sum (1/7)^((k^2+3k)/2) from k=1 to n.


1



1, 344, 825945, 13881657616, 1633163136864785, 1344980069223035633256, 7753542448037025041629822057, 312883404805904029979088478768109600, 88381817680515537538446482833052972519290401
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OFFSET

1,2


COMMENTS

Series of the kind m^((k^2+3k)/2) from k=1 to n was studied by Bernoulli and Euler.


LINKS



MATHEMATICA

aa = {}; m = 1/7; sum = 0; Do[sum = sum + m^((n + 3) n/2); AppendTo[aa, Numerator[sum]], {n, 1, 20}]; aa (*Artur Jasinski*)
Numerator[Accumulate[Table[(1/7)^((n^2+3n)/2), {n, 10}]]] (* Harvey P. Dale, Jul 21 2016 *)


PROG

(PARI) a(n) = numerator(sum(k=1, n, (1/7)^((k^2+3*k)/2))); \\ Michel Marcus, Sep 09 2013


CROSSREFS



KEYWORD

frac,nonn


AUTHOR



STATUS

approved



