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A250907 Number of (n+1) X (2+1) 0..2 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element. 1
603, 13401, 297873, 6621219, 147178899, 3271547025, 72721157625, 1616472795339, 35931555318411, 798699904707465, 17753796965556513, 394637967071813043, 8772158730705164739, 194990789577739653441, 4334327408721425197833 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 24*a(n-1) - 41*a(n-2) + 36*a(n-3).

Empirical g.f.: 9*x*(67 - 119*x + 108*x^2) / (1 - 24*x + 41*x^2 - 36*x^3). - Colin Barker, Nov 23 2018

EXAMPLE

Some solutions for n=2:

2 0 1 2 2 0 2 2 0 1 1 0 0 1 1 1 1 1 1 0 2

0 2 1 2 2 1 1 1 2 2 0 1 0 2 2 2 2 0 1 2 2

0 2 2 2 0 1 0 1 0 2 1 1 0 1 0 2 0 1 1 0 2

CROSSREFS

Column 2 of A250913.

Sequence in context: A178032 A107256 A177685 * A209550 A151626 A031792

Adjacent sequences: A250904 A250905 A250906 * A250908 A250909 A250910

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 28 2014

STATUS

approved

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Last modified January 30 21:42 EST 2023. Contains 359947 sequences. (Running on oeis4.)