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 A137500 #8 Sep 27 2020 17:33:55
%S A137500 0,0,1,5,17,51,149,439,1309,3927,11797,35423,106301,318903,956645,
%T A137500 2869807,8609293,25827879,77483893,232452191,697357085,2092071255,
%U A137500 6276212741,18828636175,56485906477,169457719431,508373162389,1525119495359,4575358494269,13726075482807
%N A137500 Binomial transform of b(n) = (0, 0, A007910).
%C A137500 b(n) is binomial transform of (0, 0, A077973).
%H A137500 Andrew Howroyd, <a href="/A137500/b137500.txt">Table of n, a(n) for n = 0..1000</a>
%H A137500 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,6).
%F A137500 a(n) = 3*a(n-1) + A009545(n-1) for n > 0.
%F A137500 From _Andrew Howroyd_, Jan 03 2020: (Start)
%F A137500 a(n) = Sum_{k=0..n-2} binomial(n, k+2)*A007910(k).
%F A137500 a(n) = 5*a(n-1) - 8*a(n-2) + 6*a(n-3) for n >= 3.
%F A137500 G.f.: x*2/((1 - 3*x)*(1 - 2*x + 2*x^2)). (End)
%t A137500 LinearRecurrence[{5,-8,6},{0,0,1},40] (* _Harvey P. Dale_, Sep 27 2020 *)
%o A137500 (PARI) concat([0,0], Vec(1/((1 - 3*x)*(1 - 2*x + 2*x^2)) + O(x^40))) \\ _Andrew Howroyd_, Jan 03 2020
%Y A137500 Cf. A007910, A009545.
%K A137500 nonn,easy
%O A137500 0,4
%A A137500 _Paul Curtz_, Apr 27 2008
%E A137500 Terms a(11) and beyond from _Andrew Howroyd_, Jan 03 2020