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A237028 Number of (n+1) X (1+1) 0..2 arrays with the maximum of every 2 X 2 subblock equal. 1
81, 563, 4042, 30045, 225731, 1709398, 12985257, 98824835, 752732146, 5735997813, 43718861747, 333254475550, 2540422933761, 19366344774803, 147636924297562, 1125499164013965, 8580187472356451, 65410743082158118, 498656791677215577 (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) = 9*a(n-1) - 83*a(n-3) + 15*a(n-4) + 60*a(n-5).

Empirical g.f.: x*(81 - 166*x - 1025*x^2 + 390*x^3 + 840*x^4) / ((1 - x)*(1 - 3*x - 3*x^2)*(1 - 5*x - 20*x^2)). - Colin Barker, Oct 21 2018

EXAMPLE

Some solutions for n=4:

..1..2....0..0....0..0....0..2....0..1....0..2....2..1....2..0....0..1....0..1

..2..0....2..1....1..2....1..1....2..0....0..1....2..2....2..2....2..1....1..0

..2..1....0..0....2..1....0..2....0..2....2..2....2..2....0..1....1..0....1..1

..2..2....1..2....2..0....1..1....0..1....0..0....0..1....1..2....1..2....1..0

..0..0....0..0....2..0....2..2....2..2....1..2....0..2....1..0....0..1....0..0

CROSSREFS

Column 1 of A237035.

Sequence in context: A209506 A139156 A237035 * A235742 A236082 A235737

Adjacent sequences:  A237025 A237026 A237027 * A237029 A237030 A237031

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 02 2014

STATUS

approved

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Last modified January 20 03:25 EST 2022. Contains 350467 sequences. (Running on oeis4.)