A188184 Number of strictly increasing arrangements of 6 numbers in -(n+4)..(n+4) with sum zero

32, 94, 227, 480, 920, 1636, 2739, 4370, 6698, 9926, 14293, 20076, 27594, 37212, 49341, 64444, 83036, 105690, 133037, 165772, 204654, 250510, 304239, 366814, 439284, 522780, 618513, 727782, 851974, 992568, 1151137, 1329352, 1528984

Offset

1,1

Comments

Row 6 of A188181

Links

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

Formula

Empirical: a(n)=3*a(n-1)-2*a(n-2)-a(n-3)+2*a(n-5)-a(n-6)-a(n-7)+2*a(n-8)-a(n-10)-2*a(n-11)+3*a(n-12)-a(n-13).

Empirical: G.f. -x*(-32 +2*x -9*x^2 -19*x^3 -28*x^4 +x^5 +5*x^6 -17*x^7 +x^8 +10*x^9 +13*x^10 -23*x^11 +8*x^12) / ( (1+x) *(1+x+x^2) *(x^4+x^3+x^2+x+1) *(x-1)^6 ). - R. J. Mathar, Mar 26 2011

Example

Some solutions for n=5
.-7...-9...-6...-4...-8...-7...-7...-6...-7...-6...-8...-9...-6...-6...-9...-8
.-5...-5...-4...-2...-6...-5...-2...-5...-3...-3...-3...-2...-3...-5...-6...-3
.-4....1...-1...-1....1...-4...-1...-2....0...-2...-2....0...-2...-4....1...-1
..2....3....2....1....2....1....0....0....1...-1...-1....2....1....0....3....1
..5....4....4....2....3....7....3....6....3....5....5....4....3....7....4....3
..9....6....5....4....8....8....7....7....6....7....9....5....7....8....7....8

Crossrefs

Sequence in context: A297730 A360436 A124804 * A126386 A208635 A259715

Adjacent sequences: A188181 A188182 A188183 * A188185 A188186 A188187

Keyword

nonn

Author

R. H. Hardin Mar 23 2011

Status

approved