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 A061044 #22 Feb 20 2023 07:24:53
%S A061044 1,900,1225,1600,2025,100,3025,3600,4225,4900,225,6400,7225,8100,9025,
%T A061044 80,11025,12100,13225,14400,625,16900,18225,19600,21025,180,24025,
%U A061044 25600,27225,28900,1225,32400,34225,36100,38025,1600,42025
%N A061044 Denominator of 1/25 - 1/n^2.
%H A061044 Reinhard Zumkeller, <a href="/A061044/b061044.txt">Table of n, a(n) for n = 5..10000</a>
%H A061044 A. H. Pfund, <a href="https://doi.org/10.1364/JOSA.9.000193">The emission of nitrogen and hydrogen in the infrared</a>, Journal of the Optical Society of America, Vol. 9, Issue 3, (1924) pp. 193-196.
%t A061044 Table[Denominator[1/5^2 - 1/n^2], {n, 7, 50}] (* _G. C. Greubel_, Jul 07 2017 *)
%o A061044 (PARI) a(n) = denominator(1/25 - 1/n^2); \\ _Michel Marcus_, Aug 15 2013
%o A061044 (Haskell)
%o A061044 import Data.Ratio ((%), denominator)
%o A061044 a061044 = denominator . (1 % 25 -) . recip . (^ 2) . fromIntegral
%o A061044 -- _Reinhard Zumkeller_, Jan 06 2014
%Y A061044 See A061041 for comments, references, links.
%Y A061044 Cf. A061043 (numerator).
%K A061044 nonn,frac
%O A061044 5,2
%A A061044 _N. J. A. Sloane_, May 26 2001