A251785 Number of (n+2)X(2+2) 0..3 arrays with no row, column, diagonal or antidiagonal in any 3X3 subblock summing to 2 3 6 or 7

1664, 2640, 6470, 14908, 35948, 85826, 210582, 525800, 1281188, 3230514, 8269042, 20728732, 53387162, 139225802, 357534236, 936054498, 2475510686, 6476921720, 17167048240, 45854800004, 121609864088, 325220317710, 874682014058

Offset

1,1

Comments

Column 2 of A251791

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +2*a(n-2) +28*a(n-3) -95*a(n-4) -81*a(n-5) -257*a(n-6) +1052*a(n-7) +1214*a(n-8) +1088*a(n-9) -5017*a(n-10) -8156*a(n-11) -5209*a(n-12) +12019*a(n-13) +24363*a(n-14) +21272*a(n-15) -22278*a(n-16) -42991*a(n-17) -38325*a(n-18) +75140*a(n-19) +137588*a(n-20) +93255*a(n-21) -173675*a(n-22) -367845*a(n-23) -268747*a(n-24) +191739*a(n-25) +549835*a(n-26) +446126*a(n-27) -59905*a(n-28) -456401*a(n-29) -424111*a(n-30) -116715*a(n-31) +102625*a(n-32) +158011*a(n-33) +147315*a(n-34) +159556*a(n-35) +105365*a(n-36) -25505*a(n-37) -115405*a(n-38) -104222*a(n-39) -37086*a(n-40) -689*a(n-41) +3639*a(n-42) +9932*a(n-43) +17510*a(n-44) +15235*a(n-45) +5127*a(n-46) -1481*a(n-47) -1542*a(n-48) -920*a(n-49) -1159*a(n-50) -968*a(n-51) -444*a(n-52) +14*a(n-53) +34*a(n-54) +15*a(n-55) +67*a(n-56) +55*a(n-57) +18*a(n-58) -6*a(n-59) -6*a(n-60) for n>66

Example

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

Crossrefs

Sequence in context: A104019 A054810 A251888 * A234976 A303643 A068744

Adjacent sequences: A251782 A251783 A251784 * A251786 A251787 A251788

Keyword

nonn

Author

R. H. Hardin, Dec 08 2014

Status

approved