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 A027154 #11 Jun 11 2025 00:59:19
%S A027154 1,1,3,5,9,15,31,49,101,163,331,533,1089,1751,3575,5753,11741,18891,
%T A027154 38563,62045,126649,203775,415951,669249,1366101,2198003,4486651,
%U A027154 7218853,14735409,23708711,48395175,77865993,158943181,255733531,522013523,839899885,1714437289,2758464335
%N A027154 a(n) = Sum_{k=0..floor(n/2)} A027144(n-k, k).
%F A027154 Conjectures from _Chai Wah Wu_, Jun 10 2025: (Start)
%F A027154 a(n) = 2*a(n-2) + 3*a(n-4) + 4*a(n-6) for n > 5.
%F A027154 G.f.: -(x^2 + 1)*(2*x^3 + x + 1)/(4*x^6 + 3*x^4 + 2*x^2 - 1). (End)
%K A027154 nonn
%O A027154 0,3
%A A027154 _Clark Kimberling_
%E A027154 More terms from _Sean A. Irvine_, Oct 24 2019