A202255 Number of zero-sum -n..n arrays of 5 elements with adjacent element differences also in -n..n.
15, 107, 397, 1077, 2385, 4643, 8211, 13533, 21091, 31461, 45241, 63135, 85861, 114251, 149145, 191501, 242277, 302561, 373433, 456105, 551777, 661793, 787469, 930277, 1091655, 1273201, 1476475, 1703201, 1955057, 2233899, 2541525, 2879915
Offset: 1
Keywords
Examples
Some solutions for n=10 .-3....5....0...-6....3....4....4...-6....1....7....4...-5...-2....4...-4...-3 .-3...-3...-9...-5...10....4....3...-4....5....0....5....1....4...-3....3....1 .-7....4....0....0....1...-1...-4....4...-2...-2....3....5....5....5....5....1 ..3...-3....7...10...-5...-7...-6...-1...-3...-5...-3...-3...-1....1....3....1 .10...-3....2....1...-9....0....3....7...-1....0...-9....2...-6...-7...-7....0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = a(n-1) +a(n-2) -a(n-5) -a(n-6) -a(n-7) +a(n-8) +a(n-9) +a(n-10) -a(n-13) -a(n-14) +a(n-15).
Empirical: G.f. -x*(15 +92*x +275*x^2 +573*x^3 +911*x^4 +1196*x^5 +1305*x^6 +1198*x^7 +913*x^8 +574*x^9 +275*x^10 +91*x^11 +13*x^12 +x^14) / ( (1+x+x^2) *(x^4+x^3+x^2+x+1) *(x^2+1) *(1+x)^2 *(x-1)^5 ). - R. J. Mathar, Dec 15 2011
Comments