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 A068200 #6 Feb 02 2024 16:13:12 %S A068200 1,2,6,24,120,696,4536,32568,254136,2133816,19130040,182000952, %T A068200 1828296888,19311334200,213709376184,2470302259512,29746381049016, %U A068200 372270346391352,4831940144914104,64925998174811448,901626111996723384,12920858504042924856 %N A068200 One of a family of sequences that interpolates between the Bell numbers and the factorials. %D A068200 G. Labelle et al., Stirling numbers interpolation using permutations with forbidden subsequences, Discrete Math. 246 (2002), 177-195. %p A068200 g:= proc(n) option remember; `if` (n=0, 1, (1+add(binomial (n-1, k-1) * g(n-k), k=1..n-1)) * 4) end: %p A068200 a:= n-> `if`(n<=1, n+1, 6*g(n-2)): seq (a(n), n=0..25); # _Sean A. Irvine_, Feb 02 2024 %Y A068200 Cf. A000110, A001861, A068199, this, A068201, ..., A000142. %K A068200 nonn %O A068200 0,2 %A A068200 _N. J. A. Sloane_, Mar 23 2002 %E A068200 More terms from _Sean A. Irvine_, Feb 02 2024