cp's OEIS Frontend

A156270 a(n) = 8^n*Catalan(n).

%I A156270 #47 Sep 08 2022 08:45:41
%S A156270 1,8,128,2560,57344,1376256,34603008,899678208,23991418880,
%T A156270 652566593536,18034567675904,504967894925312,14294475794808832,
%U A156270 408413594137395200,11762311511156981760,341107033823552471040,9952299339793060331520
%N A156270 a(n) = 8^n*Catalan(n).
%C A156270 A quarter of the count of And/Or-Trees with 2 variables [Chauvin]. - _R. J. Mathar_, Apr 01 2012
%H A156270 Vincenzo Librandi, <a href="/A156270/b156270.txt">Table of n, a(n) for n = 0..200</a>
%H A156270 Brigitte Chauvin, Philippe Flajolet, Daniele Gardy and Bernhard Gittenberger, <a href="http://dx.doi.org/10.1017/S0963548304006273">And/Or Tree Revisited</a>, Combinat., Probal. Comput., Vol. 13, No. 4-5 (2004), pp. 475-497.
%F A156270 a(n) = 8^n*A000108(n).
%F A156270 From _Gary W. Adamson_, Jul 18 2011: (Start)
%F A156270 a(n) is the upper left term in M^n, M = an infinite square production matrix:
%F A156270   8, 8, 0, 0, 0, 0, ...
%F A156270   8, 8, 8, 0, 0, 0, ...
%F A156270   8, 8, 8, 8, 0, 0, ...
%F A156270   8, 8, 8, 8, 8, 0, ...
%F A156270   ... (End)
%F A156270 E.g.f.: KummerM(1/2, 2, 32*x). - _Peter Luschny_, Aug 26 2012
%F A156270 G.f.: c(8*x) with c(x) the o.g.f. of A000108 (Catalan). - _Philippe Deléham_, Nov 15 2013
%F A156270 a(n) = Sum_{k=0..n} A085880(n,k)*7^k. - _Philippe Deléham_, Nov 15 2013
%F A156270 G.f.: 1/(1 - 8*x/(1 - 8*x/(1 - 8*x/(1 - ...)))), a continued fraction. - _Ilya Gutkovskiy_, Aug 08 2017
%F A156270 (n+1)*a(n) +16*(-2*n+1)*a(n-1)=0. - _R. J. Mathar_, Apr 14 2018
%F A156270 Sum_{n>=0} 1/a(n) = 1040/961 + 1536*arctan(1/sqrt(31)) / (961*sqrt(31)). - _Vaclav Kotesovec_, Nov 23 2021
%F A156270 Sum_{n>=0} (-1)^n/a(n) = 112/121 - 512*arctanh(1/sqrt(33)) / (363*sqrt(33)). - _Amiram Eldar_, Jan 25 2022
%F A156270 D-finite with recurrence +(n+1)*a(n) +16*(-2*n+1)*a(n-1)=0. - _R. J. Mathar_, Mar 21 2022
%t A156270 Table[8^n*CatalanNumber[n], {n, 0, 20}] (* _Wesley Ivan Hurt_, Dec 28 2013 *)
%o A156270 (Magma) [8^n*Catalan(n): n in [0..20]]; // _Vincenzo Librandi_, Jul 19 2011
%Y A156270 Cf. A000108, A005159, A085880, A151374, A151403, A156058, A156128, A156266.
%Y A156270 Column k=8 of A290605.
%K A156270 nonn,easy
%O A156270 0,2
%A A156270 _Philippe Deléham_, Feb 07 2009