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 A200153 #7 Jul 22 2025 15:42:04 %S A200153 1,8,32,158,636,3000,11370,52166,194818,841122,3338446,18901856, %T A200153 57842348,378064896,1073497924,3840517750,15453709184,133757694784, %U A200153 361144763380,2500726090816,6776168788838,17399866594576,65044240487692 %N A200153 Number of 0..7 arrays x(0..n-1) of n elements with zero n-1st difference. %C A200153 Column 7 of A200154 %H A200153 R. H. Hardin, <a href="/A200153/b200153.txt">Table of n, a(n) for n = 1..26</a> %e A200153 Some solutions for n=6 %e A200153 ..5....1....5....1....5....6....4....4....6....0....2....3....7....5....5....5 %e A200153 ..0....7....7....0....4....5....0....2....1....0....1....6....5....0....2....3 %e A200153 ..3....4....3....0....7....1....3....3....6....3....0....7....5....0....4....5 %e A200153 ..6....2....2....0....7....0....4....3....6....3....2....5....4....2....4....6 %e A200153 ..5....3....4....1....4....3....2....2....0....0....5....2....3....4....1....4 %e A200153 ..0....1....0....6....5....6....4....4....1....0....2....3....7....5....0....0 %K A200153 nonn %O A200153 1,2 %A A200153 _R. H. Hardin_ Nov 13 2011