A252857 Number of (n+2) X (4+2) 0..2 arrays with every consecutive three elements in every row, column, diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order.

1719, 1296, 1962, 3582, 7002, 13590, 26766, 52650, 104796, 207414, 410922, 815634, 1620126, 3212352, 6373728, 12654630, 25115112, 49827690, 98894880, 196294230, 389531628, 773007606, 1534206006, 3044825712, 6042454650, 11991793788

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-2) + 4*a(n-3) + 6*a(n-4) - a(n-5) - 5*a(n-6) - 5*a(n-7) + 2*a(n-9) - a(n-10) for n>12.

Empirical g.f.: 9*x*(191 + 144*x + 27*x^2 - 510*x^3 - 1162*x^4 - 433*x^5 + 395*x^6 + 733*x^7 + 170*x^8 - 284*x^9 + 63*x^10 + 26*x^11) / ((1 - x)*(1 + x)*(1 + x + x^2)*(1 - x - 3*x^3 - 3*x^4 + 3*x^5 - x^6)). - Colin Barker, Dec 07 2018

Example

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

Crossrefs

Column 4 of A252861.

Sequence in context: A252610 A237932 A276458 * A234906 A205195 A200958

Adjacent sequences: A252854 A252855 A252856 * A252858 A252859 A252860

Keyword

nonn

Author

R. H. Hardin, Dec 23 2014

Status

approved