A220801 Sum of neighbor maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to the sum mod 4 of their horizontal and vertical neighbors in a random 0..3 nX2 array

2, 16, 48, 256, 928, 4096, 15820, 65536, 259584, 1048576, 4182016, 16777216, 67051520, 268435456, 1073476576, 4294967296, 17178689536, 68719476736, 274872664064, 1099511627776, 4398023442432, 17592186044416, 70368643424320

Offset

1,1

Comments

Column 2 of A220805

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +8*a(n-2) -32*a(n-3) -16*a(n-4) +64*a(n-5) +44*a(n-8) -176*a(n-9) -352*a(n-10) +1408*a(n-11) +704*a(n-12) -2816*a(n-13) -688*a(n-16) +2752*a(n-17) +5504*a(n-18) -22016*a(n-19) -11008*a(n-20) +44032*a(n-21) +4672*a(n-24) -18688*a(n-25) -37376*a(n-26) +149504*a(n-27) +74752*a(n-28) -299008*a(n-29) -14336*a(n-32) +57344*a(n-33) +114688*a(n-34) -458752*a(n-35) -229376*a(n-36) +917504*a(n-37) +16384*a(n-40) -65536*a(n-41) -131072*a(n-42) +524288*a(n-43) +262144*a(n-44) -1048576*a(n-45)

Example

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

Crossrefs

Sequence in context: A275032 A295533 A220173 * A220250 A192388 A162442

Adjacent sequences: A220798 A220799 A220800 * A220802 A220803 A220804

Keyword

nonn

Author

R. H. Hardin Dec 21 2012

Status

approved