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

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

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

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

Adjacent sequences: A240044 A240045 A240046 * A240048 A240049 A240050

Keyword

nonn

Author

R. H. Hardin, Mar 31 2014

Status

approved