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 A036098 #15 Sep 08 2022 08:44:52 %S A036098 1,1048577,3487832977,1102998412177,96466943268401,3751525871703601, %T A036098 83448424737674977,1232713770904458977,13310586963663775777, %U A036098 112157665459056928801,772749994932560009201,4506509987380035131377 %N A036098 Centered cube numbers: a(n) = (n+1)^20 + n^20. %C A036098 Never prime because a(n) = (2n^4 + 4n^3 + 6n^2 + 4n + 1) * (n^16 + 8n^15 + 76n^14 + 392n^13 + 1394n^12 + 3632n^11 + 7112n^10 + 10656n^9 + 12376n^8 + 11220n^7 + 7942n^6 + 4356n^5 + 1819n^4 + 560n^3 + 120n^2 + 16n + 1). Semiprime for n in {1, 13, 14, 54, 162, ...}. - _Jonathan Vos Post_, Aug 27 2011 %H A036098 Vincenzo Librandi, <a href="/A036098/b036098.txt">Table of n, a(n) for n = 0..10000</a> %H A036098 B. K. Teo and N. J. A. Sloane, <a href="http://dx.doi.org/10.1021/ic00220a025">Magic numbers in polygonal and polyhedral clusters</a>, Inorgan. Chem. 24 (1985), 4545-4558. %e A036098 a(1) = 1^20 + (1+1)^20 = 1048577 = 17 * 61681, which is semiprime. %o A036098 (Magma) [(n+1)^20+n^20: n in [0..20]]; // _Vincenzo Librandi_, Aug 28 2011 %Y A036098 Cf. A010808, A036096, A036097. %K A036098 nonn,easy %O A036098 0,2 %A A036098 _N. J. A. Sloane_