A250709 Number of (2+1)X(n+1) 0..3 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

536, 4958, 37892, 253578, 1578385, 9240474, 52069631, 284450645, 1521706874, 8006080990, 41628131511, 214453424947, 1097373284793, 5586018701574, 28325119309614, 143201358726960, 722370090585231, 3637773652985792

Offset

1,1

Comments

Row 2 of A250707

Links

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

Formula

Empirical: a(n) = 19*a(n-1) -126*a(n-2) +183*a(n-3) +1796*a(n-4) -8913*a(n-5) +4573*a(n-6) +66844*a(n-7) -159500*a(n-8) -110347*a(n-9) +880170*a(n-10) -671453*a(n-11) -2023137*a(n-12) +3717534*a(n-13) +1245646*a(n-14) -7902628*a(n-15) +3640217*a(n-16) +8175766*a(n-17) -8942921*a(n-18) -2871444*a(n-19) +8558015*a(n-20) -2088628*a(n-21) -3791479*a(n-22) +2465772*a(n-23) +449922*a(n-24) -865945*a(n-25) +183465*a(n-26) +86000*a(n-27) -45400*a(n-28) +6000*a(n-29) for n>34

Example

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

Crossrefs

Sequence in context: A252275 A059949 A256088 * A077076 A033916 A236879

Adjacent sequences: A250706 A250707 A250708 * A250710 A250711 A250712

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved