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 A202248 #7 Oct 19 2021 21:41:57 %S A202248 1,5,27,171,1077,6963,45523,300417,1995897,13332697,89461271, %T A202248 602525231,4070925653,27580062519,187294750351,1274550544383, %U A202248 8689294370837,59336253329567,405779196651853,2778627840692687,19049684072515863 %N A202248 Number of zero-sum -4..4 arrays of n elements with adjacent element differences also in -4..4. %C A202248 Column 4 of A202252. %H A202248 R. H. Hardin, <a href="/A202248/b202248.txt">Table of n, a(n) for n = 1..210</a> %e A202248 Some solutions for n=7 %e A202248 ..3....0....0...-4....2...-3....0...-1....2....2...-3...-3....4....2...-1....2 %e A202248 ..3....0....2....0...-2...-4...-1....3...-2....3....0....1....1....2...-2....1 %e A202248 ..2....2....0...-3....1....0....3....1...-2....0....0....2....0...-1....1....1 %e A202248 ..1...-1...-1....1...-3....0....0....3...-1...-1....4...-2...-2....2....1...-3 %e A202248 .-3...-3...-1....3....0....4...-3...-1...-1....0....1....1...-1....0...-1...-3 %e A202248 .-3....0....0....3....1....1....0...-1....1...-3....1....1...-2...-1....2....0 %e A202248 .-3....2....0....0....1....2....1...-4....3...-1...-3....0....0...-4....0....2 %Y A202248 Cf. A202252. %K A202248 nonn %O A202248 1,2 %A A202248 _R. H. Hardin_ Dec 14 2011