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 A188361 #6 Jul 22 2025 11:10:24 %S A188361 197,1953,7369,22229,45801,100885,163745,283893,438373,678617,911709, %T A188361 1386673,1772141,2399001,3175561,4167365,5010369,6549541,7719713, %U A188361 9789981,11867065,14232893,16279425,20224801 %N A188361 Number of arrangements of 6 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero. %C A188361 Row 5 of A188358 %e A188361 Some solutions for n=4 %e A188361 ..0...-2...-2....4....2...-3...-2....3...-4....1....1...-4....4....2....2....3 %e A188361 .-3...-1...-3...-2....0...-2...-3...-1....2....0...-1....1....1....3....0....3 %e A188361 .-3....0....2....2...-2...-3....3....1...-1...-3....1...-1....4...-1....0...-3 %e A188361 ..2...-3....2....4...-3....4....4....4...-1....3....0...-3...-2....1...-1....2 %e A188361 .-1....1...-2....4....2....4...-3....0....3....3...-1....2...-4...-1....0....2 %e A188361 ..1....1....0...-3....0...-4...-1....2....4....0...-2....4....2....1....0....1 %K A188361 nonn %O A188361 1,1 %A A188361 _R. H. Hardin_ Mar 28 2011