A250636 Number of (4+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

1072, 7342, 43185, 218680, 1014946, 4416061, 18465586, 74732823, 296093261, 1152271759, 4431083756, 16868521712, 63789520796, 239860653668, 898625766687, 3356121820652, 12509696905973, 46549835501331, 173041037569515

Offset

1,1

Comments

Row 4 of A250632.

Appears to satisfy the same recurrence relation as A250588.

Links

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

Formula

Empirical: a(n) = 17*a(n-1) -101*a(n-2) +110*a(n-3) +1466*a(n-4) -6607*a(n-5) +2715*a(n-6) +50990*a(n-7) -125338*a(n-8) -69069*a(n-9) +724777*a(n-10) -770521*a(n-11) -1528585*a(n-12) +4147071*a(n-13) -616996*a(n-14) -8587972*a(n-15) +9209705*a(n-16) +6258473*a(n-17) -18241543*a(n-18) +5925196*a(n-19) +15364973*a(n-20) -15498239*a(n-21) -2690737*a(n-22) +12025570*a(n-23) -4880027*a(n-24) -3407185*a(n-25) +3581843*a(n-26) -420145*a(n-27) -810850*a(n-28) +400975*a(n-29) -4790*a(n-30) -48700*a(n-31) +15025*a(n-32) -1500*a(n-33) for n > 37.

Example

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

Crossrefs

Cf. A250632, A250588.

Sequence in context: A252260 A085337 A085338 * A329148 A014364 A031779

Adjacent sequences: A250633 A250634 A250635 * A250637 A250638 A250639

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved