This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A178187 #10 May 29 2020 17:20:58
%S A178187 1,28,2269,551368,401947273,879058686052,5767504039187173,
%T A178187 113521782003321126160,6703347705514109178621841,
%U A178187 1187477935988707898665323267628,631074461779774914374598062671491949
%N A178187 Numerators of sum (1/3)^((k^2+3k)/2) from k=1 to n.
%C A178187 Series of the kind m^((k^2+3k)/2) from k=1 to n was studied by Bernoulli and Euler.
%H A178187 Vincenzo Librandi, <a href="/A178187/b178187.txt">Table of n, a(n) for n = 1..60</a>
%t A178187 aa = {}; m = 1/3; sum = 0; Do[sum = sum + m^((n + 3) n/2); AppendTo[aa, Numerator[sum]], {n, 1, 20}]; aa (*Artur Jasinski*)
%t A178187 Accumulate[Table[(1/3)^((k^2+3k)/2),{k,20}]]//Numerator (* _Harvey P. Dale_, May 29 2020 *)
%o A178187 (PARI) a(n) = numerator(sum(k=1, n, (1/3)^((k^2+3*k)/2))); \\ _Michel Marcus_, Sep 09 2013
%Y A178187 Cf. A178184-A178193.
%Y A178187 Cf. A217628 (denominators).
%K A178187 frac,nonn
%O A178187 1,2
%A A178187 _Artur Jasinski_, May 21 2010