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 A100230 #15 Oct 18 2019 14:11:00
%S A100230 1,2,10,35,118,392,1297,4286,14158,46763,154450,510116,1684801,
%T A100230 5564522,18378370,60699635,200477278,662131472,2186871697,7222746566,
%U A100230 23855111398,78788080763,260219353690,859446141836,2838557779201
%N A100230 Main diagonal of triangle A100229.
%C A100230 Let F(x) = Product_{n >= 1} (1 + x^(4*n + 1))/(1 - x^(4*n + 3)). Let alpha = (1/2)*(3 - sqrt(13)). This sequence occurs as partial numerators in the simple continued fraction expansion of the real number F(alpha) = 1.34372 29374 22358 27049 ... = 1 + 1/(2 + 1/(1 + 1/(10 + 1/(35 + 1/(1 + 1/(118 + 1/(392 + 1/(1 + ...)))))))). - _Peter Bala_, Oct 17 2019
%H A100230 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-2,-1).
%F A100230 a(n) = 3*a(n-1) + a(n-2) + 3 for n>1, with a(0)=1, a(1)=2.
%F A100230 G.f.: Sum_{n>=1} a(n)*x^n/n = log((1-x)/(1-3*x-x^2)).
%F A100230 a(0)=1, a(1)=2, a(2)=10, a(n)=4*a(n-1)-2*a(n-2)-a(n-3). [_Harvey P. Dale_, May 06 2012]
%t A100230 LinearRecurrence[{4,-2,-1},{1,2,10},30] (* _Harvey P. Dale_, May 06 2012 *)
%o A100230 (PARI) a(n)=if(n==0,1,n*polcoeff(log((1-x)/(1-3*x-x^2)+x*O(x^n)),n))
%Y A100230 Cf. A100228, A100229.
%Y A100230 Equals A006497(n) - 1.
%K A100230 nonn
%O A100230 0,2
%A A100230 _Paul D. Hanna_, Nov 29 2004