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 A178189 #9 Sep 10 2013 02:58:39
%S A178189 1,126,78751,246096876,3845263687501,300411225586015626,
%T A178189 117348134994537353906251,229195576161205769348146484376,
%U A178189 2238238048449275091290493011484375001
%N A178189 Numerators of sum (1/5)^((k^2+3k)/2) from k=1 to n.
%C A178189 Series of the kind m^((k^2+3k)/2) from k=1 to n was studied by Bernoulli and Euler.
%H A178189 Vincenzo Librandi, <a href="/A178189/b178189.txt">Table of n, a(n) for n = 1..50</a>
%t A178189 aa = {}; m = 1/5; sum = 0; Do[sum = sum + m^((n + 3) n/2); AppendTo[aa, Numerator[sum]], {n, 1, 20}]; aa (*Artur Jasinski*)
%o A178189 (PARI) a(n) = numerator(sum(k=1, n, (1/5)^((k^2+3*k)/2))); \\ _Michel Marcus_, Sep 09 2013
%Y A178189 Cf. A178184-A178193.
%K A178189 nonn,frac
%O A178189 1,2
%A A178189 _Artur Jasinski_, May 21 2010