A241055 Number of 2 X n 0..3 arrays with no element equal to one 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.

2, 3, 2, 10, 18, 18, 46, 58, 102, 173, 264, 487, 738, 1318, 2151, 3591, 6192, 10096, 17480, 28925, 49131, 82966, 138977, 236535, 395979, 671706, 1131018, 1908201, 3226558, 5432423, 9189152, 15486612, 26156656, 44151446, 74485403, 125808822

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 3*a(n-2) + 3*a(n-3) - 3*a(n-4) - 4*a(n-5) - 2*a(n-6) + 3*a(n-7) - a(n-9) + 2*a(n-11) - 2*a(n-12) + 2*a(n-15) for n>17.

Empirical g.f.: x*(2 + 3*x - 4*x^2 - 5*x^3 + 9*x^4 - x^5 - 16*x^6 - 12*x^7 - x^8 + 3*x^9 + 3*x^10 + 11*x^12 - 10*x^13 - 8*x^14 + 6*x^15 + 8*x^16) / ((1 - x)*(1 + x - 2*x^2 - 5*x^3 - 2*x^4 + 2*x^5 + 4*x^6 + x^7 + x^8 + 2*x^9 + 2*x^10 + 2*x^12 + 2*x^13 + 2*x^14)). - Colin Barker, Oct 29 2018

Example

Some solutions for n=4:
..3..3..2..2....3..3..2..2....3..2..3..3....3..2..3..3....3..3..2..2
..2..1..1..3....2..2..0..0....2..1..1..0....2..1..1..2....2..2..0..3

Crossrefs

Row 2 of A241054.

Sequence in context: A333129 A078828 A247170 * A224418 A220947 A224417

Adjacent sequences: A241052 A241053 A241054 * A241056 A241057 A241058

Keyword

nonn

Author

R. H. Hardin, Apr 15 2014

Status

approved