A187982 Number of nondecreasing arrangements of n numbers x(i) in -(n+1)..(n+1) with the sum of sign(x(i))*2^|x(i)| zero

0, 3, 7, 22, 82, 260, 912, 3158, 10920, 38385, 134652, 474953, 1680801, 5960094, 21192029, 75492493, 269409262, 963003740, 3447075784, 12354841859, 44333177653, 159250306113, 572602762173, 2060689223094, 7422109110741, 26752896159623, 96498088175421, 348296867524920, 1257893866073062, 4545530514677703, 16434464166065112

Offset

1,2

Comments

Column 3 of A187988

Links

Table of n, a(n) for n=1..31.

Example

Some solutions for n=4
.-5...-3...-5...-4...-4...-4...-5...-4...-5...-4...-3...-3...-2...-3...-2...-5
.-5...-2...-2...-4...-3...-3...-4...-1...-1....2....1...-1...-1...-2....0...-3
..5...-2....2....4....3...-3....4....1....1....2....1....1....1....2....0....3
..5....4....5....4....4....5....5....4....5....3....2....3....2....3....1....5

Crossrefs

Sequence in context: A233005 A018190 A323930 * A000228 A108070 A038147

Adjacent sequences: A187979 A187980 A187981 * A187983 A187984 A187985

Keyword

nonn

Author

R. H. Hardin Mar 18 2011

Extensions

More terms from R. J. Mathar, May 11 2023

Status

approved