A252025 - OEIS

A252025

Number of (n+2)X(1+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 2 or 4

213, 227, 357, 809, 1805, 4259, 10251, 24331, 57385, 135913, 322129, 763095, 1807991, 4283219, 10146569, 24037921, 56947673, 134911263, 319611383, 757175635, 1793784697, 4249564025, 10067427977, 23850227423, 56502354463

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 1 of A252032

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) -a(n-2) +5*a(n-3) -2*a(n-4) +3*a(n-5) -2*a(n-6) -2*a(n-7) -2*a(n-8) -2*a(n-9) +2*a(n-11) for n>14

EXAMPLE

Some solutions for n=4

..2..1..2....1..2..2....2..1..2....2..1..2....2..1..2....2..2..2....0..2..1

..1..2..2....2..1..2....2..2..2....2..2..2....2..2..2....1..2..2....0..1..2

..2..2..1....2..2..1....2..2..2....2..2..2....2..2..2....2..2..2....1..2..2

..2..2..2....2..2..2....1..2..2....2..2..1....2..2..1....2..1..2....2..2..1

..2..2..2....2..2..2....2..1..2....2..1..2....2..1..2....2..2..2....2..2..2

..2..2..2....1..1..1....2..0..1....1..0..2....1..2..2....1..0..2....2..1..2

CROSSREFS

Sequence in context: A201104 A092126 A252032 * A238019 A251146 A085309

Adjacent sequences: A252022 A252023 A252024 * A252026 A252027 A252028

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 12 2014

STATUS

approved