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A241050
Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.
1
3, 3, 4, 6, 8, 12, 13, 20, 28, 38, 53, 68, 96, 130, 178, 245, 330, 454, 617, 841, 1153, 1563, 2144, 2913, 3982, 5431, 7404, 10111, 13783, 18809, 25665, 34995, 47772, 65135, 88894, 121250, 165416, 225685, 307854, 420020, 572988, 781677, 1066446, 1454794
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-2) - a(n-4) + a(n-5) - a(n-7) + a(n-8) + a(n-11) for n>15.
Empirical g.f.: x*(3 + 3*x - 2*x^2 + 3*x^4 - 2*x^6 + x^7 + 4*x^8 + 3*x^9 - 2*x^11 - x^12 + x^13 + 2*x^14) / ((1 + x)*(1 - x - x^2 + x^3 - x^5 + x^6 - x^8 + x^9 - x^10)). - Colin Barker, Oct 29 2018
EXAMPLE
All solutions for n=4:
..3..2....3..3....3..3....3..2....3..2....3..2
..2..0....2..0....2..2....2..0....2..0....2..0
..3..3....2..0....2..0....3..3....2..0....3..3
..3..2....2..0....2..0....2..2....2..0....2..0
CROSSREFS
Column 2 of A241054.
Sequence in context: A240115 A196249 A241036 * A363237 A080013 A152949
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 15 2014
STATUS
approved