A235556 Number of (n+1)X(1+1) 0..3 arrays with the sum of each 2X2 subblock two extreme terms minus its two median terms lexicographically nondecreasing rowwise and columnwise.

256, 2612, 23024, 180640, 1321956, 9182760, 61590128, 402719344, 2587649440, 16427598848, 103462837312, 648431897408, 4052631770944, 25299606268544, 157920835375104, 986393232739328, 6167644453234432, 38615919748243968

Offset

1,1

Comments

Column 1 of A235559

Links

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

Formula

Empirical: a(n) = 20*a(n-1) -76*a(n-2) -996*a(n-3) +8480*a(n-4) +8424*a(n-5) -279280*a(n-6) +457552*a(n-7) +4597088*a(n-8) -15344288*a(n-9) -40904192*a(n-10) +233024064*a(n-11) +149002944*a(n-12) -2177686656*a(n-13) +809190144*a(n-14) +13696091136*a(n-15) -14371325184*a(n-16) -59950127104*a(n-17) +97895484416*a(n-18) +183101051904*a(n-19) -419660306432*a(n-20) -377096103936*a(n-21) +1250719469568*a(n-22) +458326937600*a(n-23) -2681697173504*a(n-24) -102179840000*a(n-25) +4178539053056*a(n-26) -732985442304*a(n-27) -4711370539008*a(n-28) +1477085659136*a(n-29) +3778314698752*a(n-30) -1487068856320*a(n-31) -2083824599040*a(n-32) +874816471040*a(n-33) +743786414080*a(n-34) -286051532800*a(n-35) -152672665600*a(n-36) +40265318400*a(n-37) +13421772800*a(n-38)

Example

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

Crossrefs

Sequence in context: A236597 A235779 A235559 * A236624 A236620 A236505

Adjacent sequences: A235553 A235554 A235555 * A235557 A235558 A235559

Keyword

nonn

Author

R. H. Hardin, Jan 12 2014

Status

approved