

A239852


Number of n X 2 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.


1



2, 3, 5, 4, 5, 5, 6, 10, 11, 15, 16, 21, 26, 32, 41, 48, 62, 74, 94, 115, 142, 177, 216, 271, 331, 413, 508, 629, 779, 960, 1192, 1468, 1821, 2247, 2781, 3439, 4249, 5260, 6496, 8041, 9935, 12290, 15195, 18786, 23236, 28721, 35526, 43916, 54312, 67152, 83033
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OFFSET

1,1


LINKS



FORMULA

Empirical: a(n) = a(n2) + a(n5) for n>9.
Empirical g.f.: x*(2 + 3*x + 3*x^2 + x^3  x^5  2*x^6 + x^8) / (1  x^2  x^5).  Colin Barker, Oct 26 2018


EXAMPLE

All solutions for n=4:
..3..2....3..2....3..2....2..3
..2..3....2..3....2..3....3..0
..2..0....3..0....3..0....3..2
..2..0....2..3....3..2....2..3


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



