cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A204106 T(n,k)=Number of (n+1)X(k+1) 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.

Original entry on oeis.org

36, 144, 144, 576, 864, 576, 2304, 5184, 5184, 2304, 9216, 31104, 46656, 31104, 9216, 36864, 186624, 419904, 419904, 186624, 36864, 147456, 1119744, 3779136, 5738688, 3779136, 1119744, 147456, 589824, 6718464, 34012224, 78428736, 78428736
Offset: 1

Views

Author

R. H. Hardin Jan 10 2012

Keywords

Comments

Also 0..2 arrays with no 2X2 subblock having equal diagonal elements or equal antidiagonal elements
Table starts
.....36......144........576.........2304...........9216............36864
....144......864.......5184........31104.........186624..........1119744
....576.....5184......46656.......419904........3779136.........34012224
...2304....31104.....419904......5738688.......78428736.......1073134656
...9216...186624....3779136.....78428736.....1631513664......34026967296
..36864..1119744...34012224...1073134656....34026967296....1084257353088
.147456..6718464..306110016..14683622976...710001723456...34589078037504
.589824.40310784.2754990144.200937920832.14819050600704.1104253773912576

Examples

			Some solutions for n=5 k=3
..0..1..0..1....1..2..0..1....0..1..2..1....2..2..0..1....2..2..2..1
..2..1..2..1....1..2..0..1....2..1..0..0....0..1..0..2....0..0..0..1
..0..0..0..1....1..2..0..2....2..1..2..1....2..1..0..1....2..2..2..2
..1..1..2..1....1..2..0..1....2..0..2..0....2..1..2..2....0..0..0..1
..0..0..2..0....1..2..0..1....1..0..2..0....0..0..0..0....2..2..2..2
..1..1..1..1....0..2..0..1....1..0..1..1....1..2..1..2....1..0..0..1
		

Crossrefs

Column 1 is A002063
Column 2 is A067411(n+2)
Column 3 is A055995(n+2)

Formula

Empirical for column k:
k=1: T(n,k)=4*T(n-1,k)
k=2: T(n,k)=6*T(n-1,k)
k=3: T(n,k)=9*T(n-1,k)
k=4: T(n,k)=15*T(n-1,k)-270*T(n-3,k)+324*T(n-4,k)
k=5: T(n,k)=25*T(n-1,k)-45*T(n-2,k)-963*T(n-3,k)+2025*T(n-4,k)+3645*T(n-5,k)-6561*T(n-6,k)
k=6: (order 15)
k=7: (order 45)