A250692 Number of (1+1) X (n+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

104, 543, 2541, 11150, 47002, 193117, 780551, 3122604, 12415380, 49197371, 194657281, 769963978, 3046948238, 12068103705, 47849956731, 189941232872, 754813261576, 3002665654519, 11955693334901, 47642223194886

Offset

1,1

Comments

Row 1 of A250691.

Links

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

Formula

Empirical: a(n) = 16*a(n-1) - 106*a(n-2) + 376*a(n-3) - 769*a(n-4) + 904*a(n-5) - 564*a(n-6) + 144*a(n-7).

Empirical g.f.: x*(104 - 1121*x + 4877*x^2 - 11052*x^3 + 13756*x^4 - 8880*x^5 + 2304*x^6) / ((1 - x)^2*(1 - 2*x)^2*(1 - 3*x)^2*(1 - 4*x)). - Colin Barker, Feb 21 2018

Example

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

Crossrefs

Cf. A250691.

Sequence in context: A234201 A250669 A250691 * A250676 A250677 A206021

Adjacent sequences: A250689 A250690 A250691 * A250693 A250694 A250695

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved