A187999 Number of nondecreasing arrangements of n numbers x(i) in -(n+4)..(n+4) with the sum of sign(x(i))*x(i)^2 zero.

1, 7, 10, 57, 159, 862, 3796, 20224, 105208, 573982, 3155734, 17684829, 100137017, 572950408, 3306528276, 19236540159, 112697134709, 664463497819, 3940606012738, 23495237570884, 140776873966346, 847335263797688, 5121621014549082

Offset

1,2

Links

Table of n, a(n) for n=1..23.

Example

All solutions for n=3
.-5...-3...-1....0...-7...-6...-5...-4...-2...-4
..0....0....0....0....0....0....3...-3....0....0
..5....3....1....0....7....6....4....5....2....4

Crossrefs

Column 6 of A188002.

Sequence in context: A025632 A038276 A249952 * A097187 A115904 A136865

Adjacent sequences: A187996 A187997 A187998 * A188000 A188001 A188002

Keyword

nonn

Author

R. H. Hardin, Mar 18 2011

Extensions

a(17) onward from Max Alekseyev, Sep 18 2023

Status

approved