A204303 Number of (n+1)X2 0..3 arrays with the sums of 2X2 subblocks nondecreasing rightwards and downwards

256, 2400, 22500, 162000, 1166400, 7157160, 43917129, 242230104, 1336048704, 6835224000, 34969000000, 169317280000, 819821593600, 3808690804320, 17694246841209, 79642490881824, 358473938494464, 1574385768820800

Offset

1,1

Comments

Column 1 of A204309

Links

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

Formula

Empirical: a(n) = 14*a(n-1) +13*a(n-2) -1054*a(n-3) +2967*a(n-4) +33454*a(n-5) -169867*a(n-6) -541454*a(n-7) +4625257*a(n-8) +3190194*a(n-9) -78493077*a(n-10) +50028366*a(n-11) +904821757*a(n-12) -1449642566*a(n-13) -7279434457*a(n-14) +18543686566*a(n-15) +40055458932*a(n-16) -154964187016*a(n-17) -132496651172*a(n-18) +924200999576*a(n-19) +64551084752*a(n-20) -4047700697376*a(n-21) +2012370535248*a(n-22) +13035697049376*a(n-23) -12864352408128*a(n-24) -30133463273856*a(n-25) +45839946627648*a(n-26) +46455381657216*a(n-27) -109440136032768*a(n-28) -36176200943616*a(n-29) +180504791635968*a(n-30) -19331562000384*a(n-31) -200887543922688*a(n-32) +88689386225664*a(n-33) +138934646489088*a(n-34) -107005889839104*a(n-35) -46480161374208*a(n-36) +62959639855104*a(n-37) -2043273019392*a(n-38) -15231671599104*a(n-39) +4458050224128*a(n-40)

Example

Some solutions for n=4
..2..2....1..3....3..3....1..1....0..1....3..2....3..1....1..2....2..0....3..0
..0..2....1..3....3..2....3..2....1..2....1..1....1..1....1..1....1..2....2..0
..3..3....3..1....3..3....1..1....0..2....2..3....3..3....3..2....1..3....3..0
..0..2....1..3....3..2....2..3....2..1....1..1....3..1....0..3....0..3....2..0
..3..3....1..3....3..3....2..3....0..3....2..3....3..3....3..2....1..3....3..1

Crossrefs

Sequence in context: A235416 A235261 A236087 * A236083 A016780 A236041

Adjacent sequences: A204300 A204301 A204302 * A204304 A204305 A204306

Keyword

nonn

Author

R. H. Hardin Jan 14 2012

Status

approved