A250635 Number of (3+1)X(n+1) 0..2 arrays with nondecreasing 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

380, 2347, 12151, 56232, 241742, 994030, 3951204, 15376595, 58841311, 222800817, 836506982, 3124145109, 11618627925, 43097606337, 159532886234, 589803541517, 2178369414653, 8040870052968, 29666788704784, 109426537156018

Offset

1,1

Comments

Row 3 of A250632

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>29

Example

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

Crossrefs

Sequence in context: A252123 A158597 A252122 * A233952 A259520 A188307

Adjacent sequences: A250632 A250633 A250634 * A250636 A250637 A250638

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved