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 A263881 #11 Jan 22 2025 05:28:27 %S A263881 1,2,3,6,7,10,11 %N A263881 Numbers k such that k! is a "compact factorial", i.e., k! is in A169661. %C A263881 Sequence linked to A050376. %H A263881 T. M. Apostol, <a href="https://zbmath.org/?q=an:1112.11006">Review of "Compact integers and factorials" by V. Shevelev</a>, zbMATH. %H A263881 Vladimir Shevelev, <a href="https://eudml.org/doc/277854">Compact integers and factorials</a>, Acta Arith. 126 (2007), no.3, 195-236. %F A263881 a(n)! = A169661(n). %Y A263881 Cf. A050376, A054861, A169661. %K A263881 nonn,fini,full %O A263881 1,2 %A A263881 _Jonathan Sondow_, Nov 17 2015