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 A067213 #12 Dec 13 2023 14:47:15 %S A067213 1,6,36,2442,4756140,255657603186,394912380135575238, %T A067213 18212451695911558370419098,25800579898930843398657192741983084, %U A067213 1146703506910134603350506378410721970397210150 %N A067213 Number of n X n 0..5 matrices with all row and column sums equal. %e A067213 Some solutions for n=3 %e A067213 ..3..0..2....5..1..3....4..3..2....3..2..4....0..2..2....0..5..3....5..4..1 %e A067213 ..2..0..3....1..4..4....0..4..5....5..4..0....0..2..2....3..3..2....2..3..5 %e A067213 ..0..5..0....3..4..2....5..2..2....1..3..5....4..0..0....5..0..3....3..3..4 %Y A067213 Column 5 of A202784. %K A067213 nonn,more %O A067213 0,2 %A A067213 _R. H. Hardin_, Feb 20 2002 %E A067213 a(0)=1 prepended and a(6)-a(7) from _Andrew Howroyd_, May 11 2020 %E A067213 a(8)-a(9) from _Sean A. Irvine_, Dec 13 2023