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A241357
Number of 2Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4
1
3, 3, 9, 17, 23, 53, 103, 160, 344, 643, 1059, 2196, 4039, 6930, 13970, 25512, 45059, 88830, 161841, 291573, 565051, 1029968, 1879844, 3596548, 6568902, 12087395, 22908471, 41950860, 77573588, 146021963, 268115989, 497179651, 931373038
OFFSET
1,1
COMMENTS
Row 2 of A241356
LINKS
FORMULA
Empirical: a(n) = a(n-2) +8*a(n-3) -5*a(n-5) -18*a(n-6) +a(n-7) +10*a(n-8) +16*a(n-9) -5*a(n-10) -10*a(n-11) +a(n-12) +6*a(n-13) -2*a(n-14) -6*a(n-15) -a(n-16) +6*a(n-17) for n>20
EXAMPLE
Some solutions for n=4
..2..3..3..2....2..3..3..2....2..3..3..3....3..2..3..3....3..2..3..3
..2..1..1..1....2..1..1..2....2..1..2..3....3..1..1..3....3..2..2..1
CROSSREFS
Sequence in context: A331519 A285883 A232948 * A217450 A089892 A038221
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 20 2014
STATUS
approved