cp's OEIS Frontend

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.

A133648 a(n) = 2*3^n + 3^(n-1) - (n+1).

This page as a plain text file.
%I A133648 #19 May 16 2020 02:54:51
%S A133648 5,18,59,184,561,1694,5095,15300,45917,137770,413331,1240016,3720073,
%T A133648 11160246,33480767,100442332,301327029,903981122,2711943403,
%U A133648 8135830248,24407490785,73222472398,219667417239,659002251764,1977006755341
%N A133648 a(n) = 2*3^n + 3^(n-1) - (n+1).
%H A133648 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-7,3).
%F A133648 O.g.f.: -x*(5-7*x+4*x^2)/((-1+x)^2*(-1+3*x)). - _R. J. Mathar_, Jan 07 2008
%F A133648 a(n) = A108765(n-1) + A108765(n). - _Klaus Purath_, Apr 13 2020
%e A133648 a(3) = 2*3^3 + 3^2 - 4 = 2*27 + 9 - 4.
%p A133648 A133648:=n->2*3^n+3^(n-1)-(n+1): seq(A133648(n), n=1..40); # _Wesley Ivan Hurt_, Apr 18 2017
%t A133648 Table[2*3^n + 3^(n - 1) - (n + 1), {n, 1, 50}] (* _Stefan Steinerberger_, Sep 20 2007 *)
%Y A133648 Cf. A000244, A108765, A133649 (inverse binomial transform).
%K A133648 nonn,easy
%O A133648 1,1
%A A133648 _Gary W. Adamson_, Sep 19 2007