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 A271031 #3 Mar 29 2016 07:44:12 %S A271031 0,70,2268,58036,1402082,33505396,804566180,19525545192,479803630966, %T A271031 11941873574498,300926010716524,7672376906432844,197762508822690802 %N A271031 Number of nXnXn triangular 0..5 arrays with some element less than a w, nw or ne neighbor exactly once. %C A271031 Column 5 of A271034. %e A271031 Some solutions for n=4 %e A271031 .....1........1........0........0........1........0........0........2 %e A271031 ....0.1......1.2......1.2......3.3......1.1......0.4......1.1......0.2 %e A271031 ...0.2.2....0.3.4....1.2.4....0.3.3....1.1.2....4.4.4....3.5.5....0.2.3 %e A271031 ..3.3.3.4..3.3.5.5..2.2.5.4..0.3.5.5..3.2.3.4..5.5.4.5..1.5.5.5..1.2.4.5 %Y A271031 Cf. A271034. %K A271031 nonn %O A271031 1,2 %A A271031 _R. H. Hardin_, Mar 29 2016