A203723 Number of (n+1)X4 0..2 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) nondecreasing in column and row directions, respectively

326, 1632, 6249, 20290, 58048, 151649, 367595, 839916, 1825184, 3804580, 7650824, 14922063, 28339038, 52596875, 95678477, 171041225, 301149679, 523280917, 898900092, 1528951772, 2578559796, 4317146589, 7183260955, 11889652446

Offset

1,1

Comments

Column 3 of A203728

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -30*a(n-2) +31*a(n-3) +67*a(n-4) -220*a(n-5) +136*a(n-6) +300*a(n-7) -546*a(n-8) +78*a(n-9) +572*a(n-10) -494*a(n-11) -130*a(n-12) +404*a(n-13) -152*a(n-14) -100*a(n-15) +99*a(n-16) -15*a(n-17) -14*a(n-18) +7*a(n-19) -a(n-20) for n>23

Example

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

Crossrefs

Sequence in context: A138816 A138817 A158271 * A097737 A236822 A126311

Adjacent sequences: A203720 A203721 A203722 * A203724 A203725 A203726

Keyword

nonn

Author

R. H. Hardin Jan 05 2012

Status

approved