A278802 Number of nX3 0..2 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order.

10, 63, 322, 1439, 5767, 20972, 69834, 214774, 615120, 1653047, 4196501, 10123619, 23327383, 51572441, 109818385, 225997932, 450803519, 873872396, 1649976645, 3040564120, 5478446820, 9666837555, 16728604905, 28427944695, 47495149011

Offset: 1

Author

R. H. Hardin, Nov 28 2016

Keywords

• nonn

Comments

Column 3 of A278807.

Examples

			Some solutions for n=4
..1..1..0. .1..1..0. .1..0..0. .0..0..0. .1..1..0. .2..1..0. .1..0..0
..2..0..2. .2..1..1. .1..2..0. .0..0..0. .1..1..0. .2..1..0. .1..1..1
..2..2..0. .2..1..2. .1..2..1. .0..0..0. .1..1..1. .2..1..0. .1..1..1
..2..2..0. .2..1..2. .2..2..2. .1..0..0. .2..1..0. .2..2..1. .2..2..0
		

Links

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

Crossrefs

Cf. A278807.

Formula

Empirical: a(n) = (1/20922789888000)*n^16 + (1/201180672000)*n^15 + (257/1046139494400)*n^14 + (1/130636800)*n^13 + (19241/114960384000)*n^12 + (3523/1306368000)*n^11 + (241517/7315660800)*n^10 + (284771/914457600)*n^9 + (336468511/146313216000)*n^8 + (35482669/2612736000)*n^7 + (376442771/5748019200)*n^6 + (46737917/179625600)*n^5 + (361669107043/435891456000)*n^4 + (250175041/127008000)*n^3 + (375648041/121080960)*n^2 + (13891/5040)*n + 1