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 A180675 #6 Aug 01 2015 09:08:59
%S A180675 1,1,1,9,97,1041,11169,119833,1285697,13794337,148000449,1587907625,
%T A180675 17036776865,182788823089,1961154631009,21041371248697,
%U A180675 225754408665729,2422135536207937,25987269043538817,278819307278968905
%N A180675 The Ca3 sums of the Pell-Jacobsthal triangle A013609.
%C A180675 The a(n+3) represent the Ca3 sums of the Pell-Jacobsthal triangle A013609. See A180662 for information about these camel and other chess sums.
%H A180675 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (11, -3, 1).
%F A180675 a(n) = 11*a(n-1)-3*a(n-2)+a(n-3) with a(0)=1, a(1)=1 and a(2)=1.
%F A180675 a(n+2) = add(A013609(n+2*k,3*k),k=0..floor(n)).
%F A180675 GF(x) = (1-10*x-7*x^2)/(1-11*x+3*x^2-x^3).
%p A180675 nmax:=20: a(0):=1: a(1):=1: a(2):=1: for n from 3 to nmax do a(n) := 11*a(n-1)-3*a(n-2)+a(n-3) od: seq(a(n),n=0..nmax);
%t A180675 LinearRecurrence[{11,-3,1},{1,1,1},20] (* _Harvey P. Dale_, Jun 23 2013 *)
%Y A180675 Cf. A077949 (Ca1), A008998 (Ca2), A180675 (Ca3), A092467 (Ca4).
%K A180675 easy,nonn
%O A180675 0,4
%A A180675 _Johannes W. Meijer_, Sep 21 2010