A278303 Number of n X 2 0..2 arrays with rows and columns in lexicographic nondecreasing order but with exactly one mistake.

3, 32, 294, 2089, 11486, 51562, 197981, 672365, 2068221, 5862308, 15508725, 38669253, 91572377, 207221995, 450353206, 943885459, 1914477373, 3769095759, 7220896420, 13492019950, 24634260906, 44027466111, 77141909955, 132687309790

Offset

1,1

Comments

Column 2 of A278309.

Links

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

Formula

Empirical: a(n) = (1/355687428096000)*n^17 + (1/2324754432000)*n^16 + (31/1046139494400)*n^15 + (431/348713164800)*n^14 + (4033/114960384000)*n^13 + (27523/38320128000)*n^12 + (882599/80472268800)*n^11 + (103841/812851200)*n^10 + (164889503/146313216000)*n^9 + (350473933/48771072000)*n^8 + (90321617/2874009600)*n^7 + (163135657/1916006400)*n^6 + (55992583019/435891456000)*n^5 + (35685265529/145297152000)*n^4 + (926078371/1210809600)*n^3 + (234481327/201801600)*n^2 + (180371/314160)*n.

Example

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

Crossrefs

Cf. A278309.

Sequence in context: A187919 A198320 A035533 * A029502 A037792 A037673

Adjacent sequences: A278300 A278301 A278302 * A278304 A278305 A278306

Keyword

nonn

Author

R. H. Hardin, Nov 17 2016

Status

approved