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 A036099 #14 Sep 08 2022 08:44:52 %S A036099 1,2097153,10462450355,4408506864307,481235204714229, %T A036099 22413787798580981,580482814723661863,9781917900938059815, %U A036099 118642361168367135017,1109418989131512359209,8400249944258160101211,53405369853627861567323 %N A036099 Centered cube numbers: (n+1)^21 + n^21. %C A036099 After a(0) always has at least 4 prime factors, because a(n) = (2n + 1) * (n^2 + n + 1) * (n^6 + 3n^5 + 9n^4 + 13n^3 + 11n^2 + 5n + 1) * (n^12 + 6n^11 + 63n^10 + 260n^9 + 643n^8 + 1078n^7 + 1275n^6 + 1078n^5 + 650n^4 + 274n^3 + 77n^2 + 13n + 1). [_Jonathan Vos Post_, Aug 27 2011] %D A036099 B. K. Teo and N. J. A. Sloane, Magic numbers in polygonal and polyhedral clusters, Inorgan. Chem. 24 (1985), 4545-4558. %H A036099 Vincenzo Librandi, <a href="/A036099/b036099.txt">Table of n, a(n) for n = 0..10000</a> %t A036099 Total/@Partition[Range[0,20]^21,2,1] (* _Harvey P. Dale_, Jul 02 2019 *) %o A036099 (Magma) [(n+1)^21+n^21: n in [0..20]]; // _Vincenzo Librandi_, Aug 28 2011 %Y A036099 Cf. A010809, A036098, A036097. %K A036099 nonn,easy %O A036099 0,2 %A A036099 _N. J. A. Sloane_