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 A034184 #19 Jun 28 2024 11:17:23 %S A034184 1,15,111,649,3495,18189,93231,474479,2406621,12187137,61668609, %T A034184 311938233,1577602849,7977940187,40342860995,204001993697, %U A034184 1031568839407,5216271035257,26376744398811,133377264694375 %N A034184 Not necessarily symmetric n X 3 crossword puzzle grids. %H A034184 Andrew Howroyd, <a href="/A034184/b034184.txt">Table of n, a(n) for n = 1..200</a> %H A034184 Louis Marin, <a href="https://arxiv.org/abs/2406.16413">Counting Polyominoes in a Rectangle b X h</a>, arXiv:2406.16413 [cs.DM], 2024. See p. 145. %F A034184 Appears to obey a 9-term linear recurrence. - _Ralf Stephan_, May 05 2004 %F A034184 Empirical g.f.: -x*(x^8-x^7-2*x^6-9*x^5+14*x^4-11*x^3-6*x^2+5*x+1) / ((x-1)*(x^2+2*x-1)*(x^6-7*x^5+x^4+6*x^3-11*x^2+7*x-1)). - _Colin Barker_, Jun 09 2013 %Y A034184 Row 3 of A292357. %Y A034184 Column sums of A059679. %Y A034184 Cf. A001333, A034182, A034184, A034185, A034186, A034187. %K A034184 nonn %O A034184 1,2 %A A034184 _Erich Friedman_