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 A199526 #7 Dec 06 2023 20:19:07 %S A199526 1,8,60,464,3734,30484,252154,2105064,17701326,149708146,1272108368, %T A199526 10851700690,92875809416,797134845184,6858361265978,59133629878796, %U A199526 510815878314050,4419961056157870,38301854208088068,332355738077962284 %N A199526 Number of -4..4 arrays x(0..n-1) of n elements with zero sum and no two consecutive zero elements. %C A199526 Column 4 of A199530. %H A199526 R. H. Hardin, <a href="/A199526/b199526.txt">Table of n, a(n) for n = 1..200</a> %e A199526 Some solutions for n=5 %e A199526 ..2....4....4....2....1....4....3....2....0...-1....2...-4....2...-2...-4...-3 %e A199526 ..1...-3...-1...-3....1...-1...-3...-2....2....4...-2....1...-1....4...-3....4 %e A199526 .-3...-3...-1....1...-3....1....3....2...-1....3...-2....2...-1...-1....0...-2 %e A199526 ..2...-1....0....1...-2....0...-1....0....1...-4....3....3...-1...-1....3...-1 %e A199526 .-2....3...-2...-1....3...-4...-2...-2...-2...-2...-1...-2....1....0....4....2 %Y A199526 Cf. A199530. %K A199526 nonn %O A199526 1,2 %A A199526 _R. H. Hardin_, Nov 07 2011