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

Author

R. H. Hardin, Mar 18 2011

Keywords

• nonn

Examples

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

Crossrefs

Column 2 of A187988.

Extensions

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