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 A280958 #6 Apr 17 2022 22:06:43 %S A280958 30,997,9899,126267,1599234,20029500,251270618,3152475854,39530438497, %T A280958 495721552160,6216700479112,77962372076794,977711970478121, %U A280958 12261314459515967,153766955348557489,1928363669762835672 %N A280958 Number of n X 5 0..2 arrays with no element equal to more than one of its horizontal, vertical and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards. %C A280958 Column 5 of A280961. %H A280958 R. H. Hardin, <a href="/A280958/b280958.txt">Table of n, a(n) for n = 1..210</a> %e A280958 Some solutions for n=4 %e A280958 ..0..1..2..1..0. .0..1..0..1..2. .0..1..0..0..2. .0..0..1..0..0 %e A280958 ..0..2..0..2..1. .1..2..2..0..0. .1..2..1..2..0. .1..2..1..2..1 %e A280958 ..1..1..0..2..0. .0..0..1..2..2. .2..0..0..1..0. .2..0..2..0..2 %e A280958 ..0..2..1..0..1. .1..2..1..0..1. .1..1..2..1..2. .1..0..1..0..2 %Y A280958 Cf. A280961. %K A280958 nonn %O A280958 1,1 %A A280958 _R. H. Hardin_, Jan 11 2017