A187981 Number of nondecreasing arrangements of n numbers x(i) in -n..n with the sum of sign(x(i))*2^|x(i)| zero

0, 2, 5, 15, 57, 181, 632, 2199, 7593, 26706, 93724, 330555, 1170088, 4149361, 14754670, 52564714, 187595025, 670589799, 2400467901, 8603906865, 30874479617, 110907636467, 398789645747, 1435195800184, 5169318396770, 18633022691923, 67210498566801, 242590233305619, 876138147816208, 3166048659124955, 11447024096561941, 41407915745717488

Offset

1,2

Comments

Column 2 of A187988

Links

Table of n, a(n) for n=1..32.

Example

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

Crossrefs

Sequence in context: A216388 A005976 A351158 * A334155 A373768 A348365

Adjacent sequences: A187978 A187979 A187980 * A187982 A187983 A187984

Keyword

nonn

Author

_R. H. Hardin_ Mar 18 2011

Extensions

More terms from _R. J. Mathar_, May 11 2023

Status

approved