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 A011953 #9 Jul 08 2025 02:43:36 %S A011953 3,2,10,15,42,68,162,280,600,1088,2214,4112,8154,15366,30052,57208, %T A011953 111166,212982,412890,794688,1540002,2974150,5767344,11167872, %U A011953 21680832,42073640,81787057,159005154,309503502,602667098 %N A011953 Number of Barlow packings with group P3m1 that repeat after n layers. %H A011953 T. J. McLarnan, <a href="http://dx.doi.org/10.1524/zkri.1981.155.3-4.269">The numbers of polytypes in close packings and related structures</a>, Zeits. Krist. 155, 269-291 (1981). %K A011953 nonn,easy %O A011953 9,1 %A A011953 _N. J. A. Sloane_