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 A200459 #7 Jul 22 2025 15:50:28 %S A200459 14,1582,19802,115140,451708,1375006,3513884,7910100,16176994, %T A200459 30639164,54582252,92444962,150029642,234839570,356372880,526276044, %U A200459 758938962,1071722528,1485196016,2023848468,2716453852,3596089776,4701336350 %N A200459 Number of -n..n arrays x(0..6) of 7 elements with zero sum and nonzero first and second differences. %C A200459 Row 5 of A200454 %H A200459 R. H. Hardin, <a href="/A200459/b200459.txt">Table of n, a(n) for n = 1..96</a> %e A200459 Some solutions for n=3 %e A200459 .-1....2...-3....1....0...-2....1...-1....0....3....3....1...-1...-1...-1....3 %e A200459 .-3....0....3...-3....3....2....2...-3....1....2...-2...-3...-3....0...-3....1 %e A200459 ..3...-1...-3....2....0....3...-3....3....3...-1...-1....2...-1...-2....2...-2 %e A200459 ..2...-3....0...-2...-1....1...-2....2....0...-3....2...-1....3...-1....0....0 %e A200459 .-2....2....2....3....1...-2....3....0...-2...-1...-2....1....0....3...-3...-2 %e A200459 ..2....3...-2....0...-1....1...-3...-1....1...-2....1...-1....2....2....2...-1 %e A200459 .-1...-3....3...-1...-2...-3....2....0...-3....2...-1....1....0...-1....3....1 %K A200459 nonn %O A200459 1,1 %A A200459 _R. H. Hardin_ Nov 18 2011