A183914 Number of nondecreasing arrangements of n numbers in -6..6 with sum zero.
1, 7, 25, 86, 252, 676, 1656, 3788, 8150, 16660, 32540, 61108, 110780, 194668, 332578, 553981, 901723, 1437269, 2247151, 3451798, 5216252, 7764392, 11396054, 16509188, 23626234, 33427622, 46791278, 64841876, 89008530, 121095602, 163364972
Offset: 1
Keywords
Examples
Some solutions for n=4 .-5...-6...-2...-5...-3...-4...-6...-3...-4...-5...-6...-4...-4...-3...-6...-3 ..0...-1...-1....0...-3....1...-1....1...-3...-2...-3...-1...-3...-1....0...-2 ..1....1....0....0....1....1....2....1....3....2....4....2....1....1....0...-1 ..4....6....3....5....5....2....5....1....4....5....5....3....6....3....6....6
Links
- R. H. Hardin, Table of n, a(n) for n = 1..161
Formula
Empirical: a(n)=a(n-1)+2*a(n-2)-a(n-3)-a(n-4)-a(n-6)-2*a(n-7)+a(n-8)+2*a(n-9)+a(n-11)+2*a(n-12)-a(n-13)-a(n-14)+2*a(n-15)-a(n-16)-4*a(n-17)-3*a(n-20)+a(n-21)+3*a(n-22)+a(n-24)+4*a(n-25)-a(n-26)-a(n-27)+3*a(n-28)-a(n-29)-4*a(n-30)-4*a(n-33)-a(n-34)+3*a(n-35)-a(n-36)-a(n-37)+4*a(n-38)+a(n-39)+3*a(n-41)+a(n-42)-3*a(n-43)-4*a(n-46)-a(n-47)+2*a(n-48)-a(n-49)-a(n-50)+2*a(n-51)+a(n-52)+2*a(n-54)+a(n-55)-2*a(n-56)-a(n-57)-a(n-59)-a(n-60)+2*a(n-61)+a(n-62)-a(n-63)
Comments