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 A053151 #19 Jul 02 2025 16:01:59
%S A053151 1,0,3,2,9,12,31,53,116,215,446,849,1726,3320,6688,12932,25925,50297,
%T A053151 100546,195562,390257,760630,1516233,2960502,5897425,11533047,
%U A053151 22964739,44972711,89528901,175546608,349425044,685913758,1365249931,2682660933
%N A053151 Number of directed EG-convex polyominoes on the honeycomb lattice with given semiperimeter.
%D A053151 Fouad Ibn-Majdoub-Hassani, Combinatoire de polyominos et des tableaux décalés oscillants, Thèse de Doctorat. Laboratoire de Recherche en Informatique, Université Paris-Sud XI, France.
%D A053151 Alain Denise, Christoph Durr, and Fouad Ibn-Majdoub-Hassani, Enumération et génération aléatoire de polyominos convexes en réseau hexagonal (French) [enumeration and random generation of convex polyominoes in the honeycomb lattice]. In Proceedings of 9th Conference on Formal Power Series and Algebraic Combinatorics, pages 222-234, 1997.
%F A053151 G.f.: x^3*((1-2*x)*(-3+x+3*x^2+2*x^3)+(1-x-x^2)*(1-4*x^2)^(1/2))/(2*(1+x)*(1-2*x)*(1-x-x^2)*(-1+x+2*x^2+x^3)).
%t A053151 CoefficientList[Series[x^3*((1-2*x)*(-3+x+3*x^2+2*x^3)+(1-x-x^2)*(1-4*x^2)^(1/2))/(2*(1+x)*(1-2*x)*(1-x-x^2)*(-1+x+2*x^2+x^3)),{x,0,36}],x] (* _Stefano Spezia_, Oct 28 2023 *)
%K A053151 nonn,easy
%O A053151 3,3
%A A053151 _Fouad IBN MAJDOUB HASSANI_, Feb 28 2000
%E A053151 More terms from _James Sellers_, Mar 01 2000