A183929 Number of nondecreasing arrangements of n numbers in -3..3 with sum zero and sum of squares less than n*12/3

1, 2, 5, 11, 21, 36, 60, 95, 143, 212, 302, 424, 582, 784, 1034, 1355, 1736, 2207, 2776, 3455, 4252, 5213, 6315, 7607, 9105, 10826, 12786, 15053, 17595, 20488, 23752, 27416, 31497, 36092, 41169, 46821, 53078, 59989, 67574, 75963, 85103, 95134, 106094

Offset

1,2

Comments

Column 3 of A183935

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=2*a(n-1)-a(n-2)-a(n-5)+2*a(n-6)-a(n-7)+a(n-8)-a(n-9)-a(n-10)+a(n-11)+a(n-13)-a(n-14)-a(n-16)+2*a(n-18)-a(n-19)+a(n-20)-2*a(n-21)+a(n-23)+a(n-24)-a(n-25)-a(n-28)+2*a(n-29)-a(n-30)-a(n-33)+2*a(n-34)-a(n-35)-a(n-38)+a(n-39)+a(n-40)-2*a(n-42)+a(n-43)-a(n-44)+2*a(n-45)-a(n-47)-a(n-49)+a(n-50)+a(n-52)-a(n-53)-a(n-54)+a(n-55)-a(n-56)+2*a(n-57)-a(n-58)-a(n-61)+2*a(n-62)-a(n-63)

Example

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

Crossrefs

Sequence in context: A137356 A365734 A103198 * A365252 A003522 A112805

Adjacent sequences: A183926 A183927 A183928 * A183930 A183931 A183932

Keyword

nonn

Author

R. H. Hardin Jan 08 2011

Status

approved