A303243 Number of 3Xn 0..1 arrays with every element equal to 0, 2, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 2, 18, 8, 60, 56, 236, 428, 1248, 3264, 8624, 24720, 65816, 187464, 509576, 1428608, 3932112, 10932480, 30245800, 83854984, 232353544, 643805072, 1784418352, 4944349600, 13703715720, 37974373160, 105243781928, 291657188656

Offset

1,1

Comments

Row 3 of A303242.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +9*a(n-2) -28*a(n-3) -37*a(n-4) +117*a(n-5) +85*a(n-6) -280*a(n-7) -118*a(n-8) +424*a(n-9) +92*a(n-10) -428*a(n-11) -26*a(n-12) +300*a(n-13) +12*a(n-14) -172*a(n-15) +48*a(n-16) +24*a(n-17) -48*a(n-18) +8*a(n-20)

Example

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

Crossrefs

Cf. A303242.

Sequence in context: A255566 A371210 A302461 * A074676 A257505 A152883

Adjacent sequences: A303240 A303241 A303242 * A303244 A303245 A303246

Keyword

nonn

Author

R. H. Hardin, Apr 20 2018

Status

approved