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A240047
Number of 2Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of the 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
2, 4, 9, 20, 33, 76, 117, 232, 398, 675, 1228, 2002, 3548, 5935, 10128, 17287, 28967, 49649, 83130, 141412, 238567, 402406, 681948, 1147552, 1943230, 3275448, 5532679, 9343794, 15759620, 26629572, 44915334, 75854561, 128021118, 216075045
OFFSET
1,1
COMMENTS
Row 2 of A240046
LINKS
FORMULA
Empirical: a(n) = 3*a(n-2) +4*a(n-3) -3*a(n-4) -7*a(n-5) -5*a(n-6) +6*a(n-7) +4*a(n-8) +a(n-9) -3*a(n-10) +2*a(n-11) -a(n-12) -2*a(n-14) +4*a(n-15) -2*a(n-18) for n>22
EXAMPLE
Some solutions for n=3
..3..2..2....3..2..2....3..2..2....2..3..2....3..2..2....3..2..2....3..2..3
..1..0..0....2..0..3....2..1..0....3..0..0....1..0..3....2..0..0....2..1..0
CROSSREFS
Sequence in context: A034749 A353734 A053024 * A090166 A101338 A018102
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 31 2014
STATUS
approved