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 A342907 #41 May 24 2021 16:33:34 %S A342907 1,4,20,304,6784,407684,39072966,9449433606,3830070645700, %T A342907 3762885306351756,6402694828334379856,25695884677997378383120 %N A342907 a(n) is the number of tilings of the order-n Aztec Diamond by square tetrominoes and Z-shaped tetrominoes, counting all rotations and reflections as distinct. %C A342907 Computed by _Don Reble_, Mar 31 2021; a(8) from Mike Beeler, Mar 31 2021; a(9) from Walter Trump, Apr 01 2021 %C A342907 Comments from _Allan C. Wechsler_, Mar 31 2021: (Start) %C A342907 Motivated by a query from James Propp in the Math-Fun forum, Mar 28 2021. %C A342907 An Aztec Diamond of order n is a set of squares whose centers are at distance n or closer to a vertex in the taxicab metric. %C A342907 Tilings by dominoes are counted by A006125. (End) %H A342907 James Propp, <a href="https://www.jstor.org/stable/2691169">A Pedestrian Approach to a Method of Conway, or, A Tale of Two Cities</a>, Mathematics Magazine, Vol. 70, No. 5 (Dec., 1997), 327-340. %Y A342907 Cf. A006125. %K A342907 nonn,more %O A342907 1,2 %A A342907 _N. J. A. Sloane_, Mar 31 2021 %E A342907 a(10) from _Andrew Howroyd_, Apr 01 2021 %E A342907 a(11) from _Walter Trump_, Apr 06 2021 %E A342907 a(12) from _Bert Dobbelaere_, May 21 2021