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 A238366 #15 Jul 18 2024 14:47:49
%S A238366 1,2,7,12,37,62,187,312,937,1562,4687,7812,23437,39062,117187,195312,
%T A238366 585937,976562,2929687,4882812,14648437,24414062,73242187,122070312,
%U A238366 366210937,610351562,1831054687,3051757812,9155273437,15258789062,45776367187,76293945312
%N A238366 a(n) = 5*a(n-2) + 2, a(0) = 1, a(1) = 2.
%C A238366 Row sums of triangle in A152717.
%H A238366 Harvey P. Dale, <a href="/A238366/b238366.txt">Table of n, a(n) for n = 0..1000</a>
%H A238366 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,5,-5).
%F A238366 G.f.: (1+x)/((1-x)*(1-5*x^2)).
%F A238366 a(n) = Sum_{k=0..n} A152717(n,k).
%F A238366 a(2*n) = A057651(n).
%F A238366 a(2*n+1) = A125831(n+1) = 2*A003463(n+1).
%F A238366 a(n) = a(n-1) + 5*a(n-2) - 5*a(n-3), a(0) = 1, a(1) = 2, a(2) = 7.
%F A238366 a(n) = A198306(n+1) for n > 1. - _Georg Fischer_, Oct 23 2018
%t A238366 LinearRecurrence[{1,5,-5},{1,2,7},40] (* _Harvey P. Dale_, Jul 18 2024 *)
%Y A238366 Cf. A057651, A125831, A152717, A198306.
%K A238366 easy,nonn
%O A238366 0,2
%A A238366 _Philippe Deléham_, Feb 25 2014