# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a307592
Showing 1-1 of 1

%I A307592 #10 Jun 11 2022 20:17:41
%S A307592 1,2,4,11,47,296,2638,31184,460445,8121616,166019736,3851820576,
%T A307592 99905492939,2863509479104,89861971946594,3064181181957632,
%U A307592 112806282518694969,4459192457431503104,188376562263115020076,8469292812455408254464,403767081039021522624615
%N A307592 Expansion of e.g.f. (sec(x) + tan(x))*(1 - LambertW(-x)*(2 + LambertW(-x))/2).
%C A307592 Boustrophedon transform of A000272.
%H A307592 <a href="/index/Bo#boustrophedon">Index entries for sequences related to boustrophedon transform</a>
%F A307592 a(n) ~ (1 + sin(exp(-1)))/cos(exp(-1)) * n^(n-2). - _Vaclav Kotesovec_, Aug 17 2019
%t A307592 nmax = 20; CoefficientList[Series[(Sec[x] + Tan[x]) (1 - LambertW[-x] (2 + LambertW[-x])/2), {x, 0, nmax}], x] Range[0, nmax]!
%t A307592 t[n_, 0] := If[n < 1, 1, n^(n - 2)]; t[n_, k_] := t[n, k] = t[n, k - 1] + t[n - 1, n - k]; a[n_] := t[n, n]; Array[a, 21, 0]
%o A307592 (Python)
%o A307592 from itertools import islice, count, accumulate
%o A307592 def A307592_gen(): # generator of terms
%o A307592     blist = (1,2)
%o A307592     yield from blist
%o A307592     for i in count(2):
%o A307592         yield (blist := tuple(accumulate(reversed(blist),initial=i**(i-2))))[-1]
%o A307592 A307592_list = list(islice(A307592_gen(),30)) # _Chai Wah Wu_, Jun 11 2022
%Y A307592 Cf. A000111, A000272, A306880, A306881.
%K A307592 nonn
%O A307592 0,2
%A A307592 _Ilya Gutkovskiy_, Apr 17 2019

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE