cp's OEIS Frontend

A188256 Number of arrangements of 10 nonzero numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.

%I A188256 #6 Jul 22 2025 11:06:13
%S A188256 0,57808,1657632,20265640,123729664,591604824,2026547348,6250275112,
%T A188256 16132348896,38938013924
%N A188256 Number of arrangements of 10 nonzero numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.
%C A188256 Row 8 of A188249
%e A188256 Some solutions for n=4
%e A188256 .-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4
%e A188256 .-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4
%e A188256 ..1....1...-2...-1...-1....1...-2...-2...-2....1....1....1...-1...-1....1...-2
%e A188256 .-1...-4....1...-4...-4....2....4....4....2...-1...-3...-3....3...-4...-4...-2
%e A188256 .-1...-4...-4....4...-3...-1....3...-3...-2...-2...-2...-3...-3....2....4....4
%e A188256 ..1...-3....2...-3....3...-4...-4....2....2...-3...-1...-1....2....4...-1...-3
%e A188256 .-1....4....1...-4...-1....4...-1...-3...-3....1...-1....3...-4...-3...-4....1
%e A188256 .-2...-3....3....2....4....1...-4...-4....4...-4....2....2...-2...-3...-3...-2
%e A188256 ..3....2...-3....3...-4...-2....4....2....3....2...-4...-4....2....3...-4....3
%e A188256 .-2...-3....2...-2....1....1...-2....2...-2...-2....2....4....1...-4....4....1
%K A188256 nonn
%O A188256 1,2
%A A188256 _R. H. Hardin_ Mar 25 2011