A187983 Number of nondecreasing arrangements of n numbers x(i) in -(n+2)..(n+2) with the sum of sign(x(i))*2^|x(i)| zero

0, 4, 9, 30, 111, 355, 1257, 4357, 15146, 53379, 187699, 663631, 2352610, 8356208, 29754352, 106127185, 379166226, 1356700796, 4860763378, 17436188166, 62613987171, 225072940410, 809789751003, 2915986488761, 10508369260118, 37896284981596, 136756217644237, 493817776063606

Offset

1,2

Comments

Column 4 of A187988

Links

Table of n, a(n) for n=1..28.

Example

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

Crossrefs

Sequence in context: A149113 A149114 A105865 * A230056 A069103 A377288

Adjacent sequences: A187980 A187981 A187982 * A187984 A187985 A187986

Keyword

nonn

Author

R. H. Hardin Mar 18 2011

Extensions

Terms from a(16) on by R. J. Mathar, May 17 2023

Status

approved