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 A178188 #12 May 11 2023 12:29:41
%S A178188 25,3150,1956275,6105471900,95373537112525,7450675970460940650,
%T A178188 2910390496349340822268775,5684344796471297836309816409400,
%U A178188 55511156915602623492479419714357425025
%N A178188 a(n) = Sum_{k=1..n} 5^((k^2+3k)/2).
%C A178188 Series of the kind m^((k^2+3k)/2) from k=1 to n was studied by Bernoulli and Euler.
%H A178188 Vincenzo Librandi, <a href="/A178188/b178188.txt">Table of n, a(n) for n = 1..50</a>
%t A178188 aa = {}; m = 5; sum = 0; Do[sum = sum + m^((n + 3) n/2); AppendTo[aa, sum], {n, 1, 20}]; aa (*Artur Jasinski*)
%t A178188 Table[Sum[5^((k^2+3k)/2),{k,n}],{n,10}] (* _Harvey P. Dale_, Jan 17 2015 *)
%o A178188 (PARI) a(n) = sum(k=1, n, 5^((k^2+3*k)/2)); \\ _Michel Marcus_, Sep 09 2013
%Y A178188 Cf. A178184-A178193.
%K A178188 nonn
%O A178188 1,1
%A A178188 _Artur Jasinski_, May 21 2010