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 A099977 #15 Jun 22 2022 14:44:59
%S A099977 1,5,52,877,21147,678570,27644437,1382958545,82864869804,
%T A099977 5832742205057,474869816156751,44152005855084346,4638590332229999353,
%U A099977 545717047936059989389,71339801938860275191172
%N A099977 Bisection of Bell numbers, A000110.
%F A099977 E.g.f.: exp(-1)*Sum_{n>=0} n*exp(n^2*x)/n!. - _Vladeta Jovovic_, Aug 24 2006
%F A099977 a(n) = exp(-1) * Sum_{k>=0} k^(2*n+1)/k!. - _Ilya Gutkovskiy_, Jun 13 2019
%p A099977 G:=series(exp(exp(x)-1),x=0,50): seq((2*n-1)!*coeff(G,x^(2*n-1)),n=1..18);
%o A099977 (Python)
%o A099977 from itertools import accumulate, islice
%o A099977 def A099977_gen(): # generator of terms
%o A099977 yield 1
%o A099977 blist, b = (1,2), 1
%o A099977 while True:
%o A099977 for _ in range(2):
%o A099977 blist = list(accumulate(blist, initial=(b:=blist[-1])))
%o A099977 yield b
%o A099977 A099977_list = list(islice(A099977_gen(),30)) # _Chai Wah Wu_, Jun 22 2022
%Y A099977 Cf. A000110, A020557.
%K A099977 nonn,easy
%O A099977 0,2
%A A099977 _N. J. A. Sloane_, Nov 19 2004
%E A099977 More terms from _Emeric Deutsch_, Dec 07 2004