A204104 Number of (n+1)X7 0..2 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that b(i,j)*b(i-1,j)-c(i,j)*c(i,j-1) is nonzero

36864, 1119744, 34012224, 1073134656, 34026967296, 1084257353088, 34589078037504, 1104253773912576, 35260853693757696, 1126080474692243328, 35963576641587458304, 1148590432691774845056, 36683475387804277514496

Offset

1,1

Comments

Also 0..2 arrays with no 2X2 subblock having equal diagonal elements or equal antidiagonal elements

Links

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

Formula

Empirical: a(n) = 39*a(n-1) +117*a(n-2) -13419*a(n-3) +42120*a(n-4) +1465776*a(n-5) -7558272*a(n-6) -59591376*a(n-7) +389959596*a(n-8) +776691180*a(n-9) -7353962460*a(n-10) -230291100*a(n-11) +53356676400*a(n-12) -41452398000*a(n-13) -124357194000*a(n-14) +143489070000*a(n-15)

Example

Some solutions for n=5
..2..0..0..2..1..2..1....2..1..0..2..1..2..2....2..0..0..0..2..0..2
..1..1..1..2..0..2..0....2..1..0..2..0..0..0....2..1..1..1..1..0..2
..2..2..0..2..0..1..0....0..1..0..1..1..2..2....2..0..0..2..2..0..2
..0..1..0..2..0..1..2....0..1..2..2..0..0..1....1..1..1..1..1..0..1
..2..2..0..1..0..1..2....2..1..0..1..1..2..1....2..0..2..2..2..0..1
..0..1..0..1..2..1..2....2..1..2..2..0..2..0....1..0..1..0..1..0..1

Crossrefs

Sequence in context: A187032 A251386 A175748 * A229509 A223304 A190383

Adjacent sequences: A204101 A204102 A204103 * A204105 A204106 A204107

Keyword

nonn

Author

R. H. Hardin Jan 10 2012

Status

approved