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 A200190 #7 Jul 22 2025 15:43:53 %S A200190 1,12,66,426,2794,18838,127800,881008,6081086,42452472,296258332, %T A200190 2085263400,14662923954,103810065802,734016517080,5219300699654, %U A200190 37060739113354,264413563521598,1883784631395118,13476226807283384 %N A200190 Number of -6..6 arrays x(0..n-1) of n elements with zero sum, adjacent elements differing by more than one, and elements alternately increasing and decreasing. %C A200190 Column 6 of A200192 %H A200190 R. H. Hardin, <a href="/A200190/b200190.txt">Table of n, a(n) for n = 1..200</a> %e A200190 Some solutions for n=5 %e A200190 ..4....3...-1....4....0....2...-2....1....4....5...-2...-6....6...-1...-2....2 %e A200190 .-6...-3....6...-6....5....4....2....3...-2...-6...-4....4...-5....5...-5...-2 %e A200190 ..4...-1...-6....1...-5...-6...-5...-4....5....2....2....2....5...-4....6....0 %e A200190 .-4...-3....2...-4....2....3....6....5...-5...-3....0....6...-4....2...-1...-3 %e A200190 ..2....4...-1....5...-2...-3...-1...-5...-2....2....4...-6...-2...-2....2....3 %K A200190 nonn %O A200190 1,2 %A A200190 _R. H. Hardin_ Nov 14 2011