A220933 Equals two maps: number of nX4 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..2 nX4 array

4, 52, 673, 9107, 123958, 1686304, 22931365, 311813067, 4239917031, 57652874111, 783943412638, 10659785895199, 144948006719997, 1970951840091756, 26800307525626867, 364421123267042408, 4955269821323438717

Offset

1,1

Comments

Column 4 of A220935

Links

R. H. Hardin, Table of n, a(n) for n = 1..156

Formula

Empirical: a(n) = 28*a(n-1) -296*a(n-2) +1804*a(n-3) -7384*a(n-4) +21847*a(n-5) -48816*a(n-6) +85558*a(n-7) -123954*a(n-8) +160701*a(n-9) -200185*a(n-10) +236867*a(n-11) -248056*a(n-12) +226758*a(n-13) -197374*a(n-14) +171224*a(n-15) -136118*a(n-16) +103073*a(n-17) -90758*a(n-18) +83397*a(n-19) -61987*a(n-20) +38070*a(n-21) -26150*a(n-22) +15689*a(n-23) -3389*a(n-24) -92*a(n-25) -312*a(n-26) +112*a(n-27) -16*a(n-28)

Example

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

Crossrefs

Sequence in context: A144339 A155661 A198281 * A222321 A222138 A006760

Adjacent sequences: A220930 A220931 A220932 * A220934 A220935 A220936

Keyword

nonn

Author

R. H. Hardin Dec 25 2012

Status

approved