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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 1
36864, 1119744, 34012224, 1073134656, 34026967296, 1084257353088, 34589078037504, 1104253773912576, 35260853693757696, 1126080474692243328, 35963576641587458304, 1148590432691774845056, 36683475387804277514496 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 21 16:16 EDT 2018. Contains 305624 sequences. (Running on oeis4.)