A250587 Number of (n+1)X(3+1) 0..2 arrays with nondecreasing max(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction

639, 3641, 17718, 79415, 333355, 1347397, 5284985, 20355558, 77281643, 290814703, 1086782674, 4044122800, 14999512012, 55523390718, 205218626587, 757840894067, 2796700223479, 10316975388347, 38048035207739, 140296439330149

Offset

1,1

Comments

Column 3 of A250592

Links

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

Formula

Empirical: a(n) = 13*a(n-1) -54*a(n-2) -4*a(n-3) +674*a(n-4) -1673*a(n-5) -904*a(n-6) +9791*a(n-7) -10723*a(n-8) -16532*a(n-9) +44343*a(n-10) -9985*a(n-11) -62272*a(n-12) +59755*a(n-13) +25323*a(n-14) -65551*a(n-15) +16714*a(n-16) +28793*a(n-17) -19289*a(n-18) -3357*a(n-19) +6590*a(n-20) -1131*a(n-21) -848*a(n-22) +336*a(n-23) +12*a(n-24) -23*a(n-25) +3*a(n-26) for n>27

Example

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

Crossrefs

Sequence in context: A281884 A200710 A250661 * A293922 A027885 A097105

Adjacent sequences: A250584 A250585 A250586 * A250588 A250589 A250590

Keyword

nonn

Author

R. H. Hardin, Nov 25 2014

Status

approved