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A203819 Number of (n+1)X2 0..3 arrays with no 2X2 subblock having equal diagonal elements or equal antidiagonal elements 1
144, 1296, 11664, 104976, 944784, 8503056, 76527504, 688747536, 6198727824, 55788550416, 502096953744, 4518872583696, 40669853253264, 366028679279376, 3294258113514384, 29648323021629456, 266834907194665104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A203826

LINKS

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

FORMULA

Empirical: a(n) = 16*9^n

EXAMPLE

Some solutions for n=4

..2..0....3..2....1..0....1..1....1..1....1..0....1..3....2..0....1..0....0..2

..2..3....0..1....1..0....3..2....2..0....3..3....0..2....2..0....1..2....0..3

..0..1....0..2....3..2....3..0....2..3....0..1....3..1....1..0....3..2....0..2

..2..3....0..1....3..0....1..1....1..0....0..1....2..0....3..2....0..0....0..3

..2..3....2..1....1..0....2..2....3..2....3..2....1..0....3..2....3..1....1..1

CROSSREFS

Sequence in context: A211473 A203826 A261655 * A222515 A023096 A223435

Adjacent sequences:  A203816 A203817 A203818 * A203820 A203821 A203822

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 06 2012

STATUS

approved

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Last modified January 15 19:06 EST 2019. Contains 319171 sequences. (Running on oeis4.)