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 A039764 #23 Apr 30 2025 10:14:02
%S A039764 1,1,4,15,72,403,2546,17867,137528,1149079,10335766,99425087,
%T A039764 1017259964,11018905667,125860969266,1510764243699,18999827156304,
%U A039764 249687992188015,3420706820299374,48751337014396167
%N A039764 D-analogs of Bell numbers.
%H A039764 Hasan Arslan, Nazmiye Alemdar, Mariam Zaarour, and Hüseyin Altındiş, <a href="https://arxiv.org/abs/2504.16522">On Bell numbers of type D</a>, arXiv:2504.16522 [math.CO], 2025. See p. 4.
%H A039764 Ruedi Suter, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL3/SUTER/sut1.html">Two analogues of a classical sequence</a>, J. Integer Sequences, Vol. 3 (2000), #P00.1.8.
%F A039764 E.g.f.: (exp(x) - x)*exp(1/2*(exp(2*x) - 1)).
%F A039764 a(n) = Sum_{k=0..n} A039760(n, k).
%t A039764 Range[0, 25]! CoefficientList[Series[(Exp[x] - x) Exp[1/2 (Exp[2 x] - 1)], {x, 0, 25}], x] (* _Vincenzo Librandi_, May 03 2015 *)
%o A039764 (PARI) x='x+O('x^30); Vec(serlaplace((exp(x) - x)*exp(1/2*(exp(2*x) - 1)))) \\ _Michel Marcus_, May 03 2015
%Y A039764 B-analogs of Bell numbers = A007405.
%K A039764 nonn
%O A039764 0,3
%A A039764 Ruedi Suter (suter(AT)math.ethz.ch)