A230660 Number of nX7 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j)

0, 63, 1155, 11745, 477279, 3951657, 169006665, 1374288243, 59075291211, 479621050353, 20625942501183, 167435671598913, 7200781142959245, 58453268091967479, 2513864130034802115, 20406595554618417837

Offset

1,2

Comments

Column 7 of A230661

Links

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

Formula

Empirical: a(n) = 390*a(n-2) -14687*a(n-4) +146138*a(n-6) -823339*a(n-8) -2774563*a(n-10) +26807114*a(n-12) -60400888*a(n-14) +106367378*a(n-16) -35490451*a(n-18) -7548040169*a(n-20) +1542760687*a(n-22) +7961883650*a(n-24) +3473400076*a(n-26) +61902164677*a(n-28) +25546220017*a(n-30) +84369583536*a(n-32) +75320917456*a(n-34) +42723111397*a(n-36) -5387877662*a(n-38) +926204972*a(n-40) -121037200*a(n-42) +10124352*a(n-44) +414720*a(n-46) for n>47

Example

Some solutions for n=5
..x..0..x..1..x..2..x....x..0..x..1..x..1..x....x..0..x..0..x..0..x
..2..x..0..x..1..x..0....0..x..2..x..1..x..1....0..x..2..x..2..x..0
..x..1..x..2..x..2..x....x..2..x..1..x..0..x....x..2..x..2..x..2..x
..0..x..1..x..2..x..0....0..x..1..x..2..x..1....2..x..0..x..2..x..1
..x..2..x..1..x..0..x....x..2..x..0..x..1..x....x..0..x..0..x..1..x

Crossrefs

Sequence in context: A258004 A258014 A183076 * A132465 A202983 A107319

Adjacent sequences: A230657 A230658 A230659 * A230661 A230662 A230663

Keyword

nonn

Author

R. H. Hardin, Oct 27 2013

Status

approved