A253700 Number of (3+1)X(n+1) 0..1 arrays with every 2X2 subblock ne-sw antidiagonal difference unequal to its neighbors horizontally and nw+se diagonal sum unequal to its neighbors vertically

104, 146, 234, 356, 618, 968, 1608, 2558, 4278, 6854, 11266, 18192, 29910, 48348, 79116, 128376, 209934, 340652, 556268, 904160, 1475412, 2398716, 3911988, 6364810, 10375264, 16884488, 27516618, 44793406, 72982490, 118821772

Offset

1,1

Comments

Row 3 of A253698

Links

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

Formula

Empirical: a(n) = 2*a(n-2) +2*a(n-4) +2*a(n-5) -3*a(n-6) +a(n-7) -a(n-8) -6*a(n-9) +2*a(n-10) -2*a(n-12) -3*a(n-13) +a(n-14) +6*a(n-15) +a(n-16) +a(n-17) -a(n-18) -a(n-19) for n>21

Example

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

Crossrefs

Sequence in context: A274357 A052476 A297912 * A260922 A054903 A074228

Adjacent sequences: A253697 A253698 A253699 * A253701 A253702 A253703

Keyword

nonn

Author

R. H. Hardin, Jan 09 2015

Status

approved