A237855 Number of (n+1)X(4+1) 0..1 arrays with no element greater than all horizontal neighbors or less than all vertical neighbors

12, 114, 773, 4826, 31651, 213165, 1428967, 9520138, 63406826, 422805151, 2820139782, 18807174933, 125411082761, 836287781961, 5576801777184, 37189049253066, 247995097101165, 1653753070681134, 11028044588822481

Offset

1,1

Comments

Column 4 of A237859

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -20*a(n-2) +71*a(n-3) +6*a(n-4) +62*a(n-5) +230*a(n-6) +271*a(n-7) -483*a(n-8) -760*a(n-9) -1175*a(n-10) +355*a(n-11) +1437*a(n-12) +407*a(n-13) -1089*a(n-14) -275*a(n-15) +318*a(n-16) +82*a(n-17) -25*a(n-18) -17*a(n-19) -a(n-20) +a(n-21)

Example

Some solutions for n=5
..1..1..1..1..1....0..1..1..1..1....1..1..1..1..1....0..1..1..0..0
..0..1..1..1..1....0..1..1..1..0....0..1..1..1..1....0..1..1..0..0
..0..0..0..0..0....0..1..1..1..0....0..1..1..1..1....0..1..1..0..0
..0..0..0..0..0....0..0..1..1..1....0..1..1..1..1....1..1..1..0..0
..0..0..1..1..0....0..0..0..1..1....1..1..0..1..1....0..1..1..1..0
..0..0..1..1..0....1..1..0..1..1....1..1..0..1..1....0..1..1..1..0

Crossrefs

Sequence in context: A198375 A124651 A231379 * A055287 A080630 A005543

Adjacent sequences: A237852 A237853 A237854 * A237856 A237857 A237858

Keyword

nonn

Author

R. H. Hardin, Feb 14 2014

Status

approved