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A203791 Number of (n+1) X 4 0..3 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements. 1
5488, 142192, 3784288, 101071600, 2700695728, 72168659104, 1928524187248, 51534966781936, 1377142783787488, 36800688925407472, 983406168592794928, 26279064902536667680, 702242139855909029488, 18765660986075071030384 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 3 of A203796.
LINKS
FORMULA
Empirical: a(n) = 31*a(n-1) -117*a(n-2) +72*a(n-3).
Empirical g.f.: 16*x*(343 - 1746*x + 1152*x^2) / (1 - 31*x + 117*x^2 - 72*x^3). - Colin Barker, Jun 05 2018
EXAMPLE
Some solutions for n=4:
..0..0..1..2....1..0..3..3....3..2..3..0....1..3..2..2....1..1..1..3
..0..3..0..1....3..1..0..3....1..3..1..3....0..1..3..2....3..1..2..1
..1..0..1..2....2..3..1..0....2..1..2..1....1..0..1..3....0..3..1..1
..1..1..0..1....3..2..3..1....0..2..2..2....2..1..1..1....3..1..0..1
..1..0..3..0....1..3..2..3....0..0..2..0....0..2..1..0....1..0..2..0
CROSSREFS
Cf. A203796.
Sequence in context: A251962 A251956 A232153 * A137816 A138760 A251885
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2012
STATUS
approved

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Last modified June 13 15:51 EDT 2024. Contains 373389 sequences. (Running on oeis4.)