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 A264830 #3 Nov 26 2015 07:06:06 %S A264830 1,4,33,288,5400,165333,4348623,208444341 %N A264830 Number of nX3 arrays of permutations of 0..n*3-1 with rows nondecreasing modulo 4 and columns nondecreasing modulo 7. %C A264830 Column 3 of A264831. %e A264830 Some solutions for n=4 %e A264830 ..0.11..7....8..0..1....8..0..7....8..0..2....0..1..7....8..0..9....0..8..7 %e A264830 ..8..4..1...10..7..3....9..1..3....1..7..3....8.10..2...11..7..3....4..1..9 %e A264830 ..9..5..3....4..9.11....4..2.10....9..5.10....9.11..3....4..1.10....5..2..3 %e A264830 ..2..6.10....5..2..6....5..6.11....4..6.11....4..5..6....5..2..6....6.10.11 %Y A264830 Cf. A264831. %K A264830 nonn %O A264830 1,2 %A A264830 _R. H. Hardin_, Nov 26 2015