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A239851 Number of n X 1 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4. 10
2, 2, 4, 6, 8, 14, 20, 30, 48, 70, 108, 166, 248, 382, 580, 878, 1344, 2038, 3100, 4726, 7176, 10926, 16628, 25278, 38480, 58534, 89036, 135494, 206104, 313566, 477092, 725774, 1104224, 1679958, 2555772, 3888406, 5915688, 8999950, 13692500 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 1 of A239858.
LINKS
FORMULA
Empirical: a(n) = a(n-2) +2*a(n-3).
Empirical g.f.: 2*x*(1 + x + x^2) / (1 - x^2 - 2*x^3). - Colin Barker, Feb 18 2018
EXAMPLE
All solutions for n=4:
..3....3....2....2....2....3
..2....2....3....3....3....2
..3....3....3....2....3....2
..2....3....3....2....2....2
CROSSREFS
Sequence in context: A266949 A255710 A329137 * A153958 A216214 A269298
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 28 2014
STATUS
approved

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Last modified March 1 09:59 EST 2024. Contains 370432 sequences. (Running on oeis4.)