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 A136660 #6 Jan 26 2023 10:14:19 %S A136660 1,18,255,3465,47880,687960,10372320,164656800,2754259200,48518870400, %T A136660 899026128000,17495593315200,356995102464000,7625049239808000, %U A136660 170196434343936000,3963602854987776000,96160451873181696000 %N A136660 Unsigned fourth column (k=3) of triangle A136656 divided by 8. %C A136660 Also unsigned third column of triangle A136657 divided by 4. %D A136660 Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, Table 8.3, p. 311, with s=-2, k=3 column/8. %F A136660 a(n) = |A136656(n+3,3)|/8, n>=0. %F A136660 E.g.f.: (2+18*x+3*x^2-12*x^3+3*x^4)/(2*(1-x)^9) (derived from the one given for the column k=3 under A136656). %Y A136660 Cf. A136656, A136659 (column k=2), A136661 (column k=4). %K A136660 nonn,easy %O A136660 0,2 %A A136660 _Wolfdieter Lang_, Feb 22 2008