A185771 Number of (n+1) X 2 0..2 arrays with no 2 X 2 subblock sum equal to any horizontal or vertical neighbor 2 X 2 subblock sum.

81, 558, 3844, 26784, 186624, 1296000, 9000000, 62568000, 434972736, 3022785216, 21006444096, 146001569472, 1014758051904, 7052535822528, 49014897132096, 340658500222656, 2367611084874816, 16455017381102784, 114363207176279616

Offset

1,1

Comments

Column 1 of A185777.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)= 3*a(n-1) +96*a(n-3) +504*a(n-4) +792*a(n-5) +2304*a(n-6) -13824*a(n-8) -13824*a(n-9).

Empirical: G.f.: -x*(-81 -315*x -2170*x^2 -7476*x^3 -11880*x^4 -21720*x^5 +25200*x^6 +177120*x^7 +155520*x^8) / ( (24*x^3+24*x^2+3*x-1) *(576*x^6-72*x^4-24*x^2-1) ). - R. J. Mathar, Jan 08 2015

Example

Some solutions for 3 X 2:
..2..1....0..2....2..1....2..1....0..1....0..2....1..2....0..0....2..1....0..1
..0..2....2..2....0..1....1..1....2..1....1..0....2..0....2..1....0..2....0..2
..0..0....0..0....1..0....0..2....2..0....2..2....1..1....1..1....1..1....2..2

Crossrefs

Sequence in context: A185777 A253482 A186141 * A186133 A209506 A139156

Adjacent sequences: A185768 A185769 A185770 * A185772 A185773 A185774

Keyword

nonn

Author

R. H. Hardin Feb 03 2011

Status

approved