A231039 Number of 3Xn 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3 and at least one element with value (x(i,j)-1) mod 3, and upper left element zero

0, 2, 10, 72, 736, 9726, 96882, 1194032, 13187232, 153259946, 1737128710, 19948288212, 227507930240, 2603987906862, 29749619767922, 340201024608192, 3888458795003620, 44455865446152198, 508187478024077774

Offset

1,2

Comments

Row 3 of A231037

Links

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

Formula

Empirical: a(n) = 8*a(n-1) +38*a(n-2) -21*a(n-3) +593*a(n-4) -2481*a(n-5) +6103*a(n-6) -35078*a(n-7) +39784*a(n-8) -114782*a(n-9) +159699*a(n-10) -69118*a(n-11) +366053*a(n-12) -98474*a(n-13) +28302*a(n-14) -573226*a(n-15) +88459*a(n-16) -277421*a(n-17) +257094*a(n-18) -82472*a(n-19) +91562*a(n-20) +91508*a(n-21) -46394*a(n-22) +30291*a(n-23) +46672*a(n-24) -9860*a(n-25) -11410*a(n-26) -12720*a(n-27) +288*a(n-28) +2176*a(n-29) +3080*a(n-30) -832*a(n-31) -192*a(n-32) +32*a(n-33) for n>34

Example

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

Crossrefs

Sequence in context: A144011 A238085 A277502 * A224799 A275550 A243250

Adjacent sequences: A231036 A231037 A231038 * A231040 A231041 A231042

Keyword

nonn

Author

R. H. Hardin, Nov 03 2013

Status

approved