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 A188360 #7 Jul 22 2025 11:10:16 %S A188360 91,565,1775,4201,8051,14477,22583,34625,49755,69749,91855,123945, %T A188360 155779,197533,247399,304785,361755,440021,512415,611097,715123, %U A188360 826765,936711,1090865,1233531,1393541,1568623,1774089,1955795,2212029,2421127,2686881 %N A188360 Number of arrangements of 5 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero. %C A188360 Row 4 of A188358 %H A188360 R. H. Hardin, <a href="/A188360/b188360.txt">Table of n, a(n) for n = 1..47</a> %e A188360 Some solutions for n=4 %e A188360 ..4....1....4...-3...-2...-1....1...-4...-3....2....3...-1....1....3...-2....0 %e A188360 ..1...-4....3....1....0....3....3...-3....0....0....0....0....0...-1....2....0 %e A188360 ..1....4...-2...-2...-1....0....3....0...-4...-2...-2....3....4...-3....2...-2 %e A188360 .-1....4....2...-1....0...-1...-2...-3....0....0....0....3....0....1...-1....0 %e A188360 ..4....1...-1...-3....0...-3....3....4....1....1....2...-3...-4....3...-2....2 %K A188360 nonn %O A188360 1,1 %A A188360 _R. H. Hardin_ Mar 28 2011