A214596 Number of 3X3X3 triangular 0..n arrays with every horizontal row having the same average value

2, 23, 62, 157, 312, 601, 986, 1619, 2426, 3589, 5028, 6997, 9314, 12371, 15914, 20377, 25488, 31789, 38846, 47399, 56906, 68161, 80592, 95137, 111002, 129383, 149342, 172141, 196800, 224761, 254762, 288563, 324722, 365077, 408132, 455941, 506666

Offset

1,1

Comments

Row 3 of A214595

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 3*a(n-2) +2*a(n-3) -3*a(n-4) -6*a(n-5) +6*a(n-7) +3*a(n-8) -2*a(n-9) -3*a(n-10) +a(n-12).

Empirical: G.f. ( -x*(2+23*x+56*x^2+84*x^3+86*x^4+87*x^5+60*x^6+23*x^7-2*x^9+x^11) ) / ( (1+x+x^2)^2*(1+x)^3*(x-1)^5 ). - R. J. Mathar, Jul 23 2012

Example

Some solutions for n=4
....3......2......1......1......2......2......3......2......3......2......2
...2.4....1.3....1.1....2.0....3.1....0.4....3.3....1.3....4.2....4.0....0.4
..2.4.3..3.2.1..1.0.2..1.1.1..3.1.2..2.0.4..3.2.4..3.3.0..2.3.4..1.2.3..0.3.3

Crossrefs

Sequence in context: A247603 A102385 A290226 * A226490 A217113 A042679

Adjacent sequences: A214593 A214594 A214595 * A214597 A214598 A214599

Keyword

nonn

Author

R. H. Hardin Jul 22 2012

Status

approved