A278728 - OEIS

A278728

Number of n X 2 0..3 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake.

%I #7 Jun 09 2023 08:18:19

%S 6,152,1947,17352,121520,712406,3633649,16547278,68531079,261693631,

%T 931194981,3113638802,9849622993,29642927267,85271613063,235393492799,

%U 625708778733,1606286648601,3992748071821,9631887926896,22595573914587

%N Number of n X 2 0..3 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake.

%C Column 2 of A278734.

%H R. H. Hardin, <a href="/A278728/b278728.txt">Table of n, a(n) for n = 1..210</a>

%H R. H. Hardin, <a href="/A278728/a278728.txt">Empirical polynomial of degree 28</a>

%F Empirical polynomial of degree 28 (see link above).

%e Some solutions for n=4

%e ..2..2. .1..1. .2..1. .1..1. .2..0. .1..0. .3..0. .0..0. .1..1. .2..2

%e ..3..0. .1..1. .2..2. .3..2. .3..2. .3..2. .3..0. .3..1. .2..1. .3..0

%e ..0..2. .0..0. .1..0. .2..2. .0..0. .0..0. .3..0. .1..0. .2..2. .2..3

%e ..0..2. .1..1. .1..0. .2..3. .2..0. .0..1. .2..1. .1..0. .1..0. .3..2

%Y Cf. A278734.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 27 2016