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.

A228506 T(n,k)=Number of nXk binary arrays with top left value 1 and no two ones adjacent horizontally, vertically, diagonally or antidiagonally.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 3, 3, 3, 3, 5, 5, 12, 5, 5, 8, 11, 29, 29, 11, 8, 13, 21, 88, 87, 88, 21, 13, 21, 43, 239, 358, 358, 239, 43, 21, 34, 85, 684, 1252, 2002, 1252, 684, 85, 34, 55, 171, 1909, 4749, 9528, 9528, 4749, 1909, 171, 55, 89, 341, 5392, 17285, 49101, 59839, 49101
Offset: 1

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Author

R. H. Hardin Aug 23 2013

Keywords

Comments

Table starts
..1...1....2.....3.......5........8........13.........21..........34
..1...1....3.....5......11.......21........43.........85.........171
..2...3...12....29......88......239.......684.......1909........5392
..3...5...29....87.....358.....1252......4749......17285.......64235
..5..11...88...358....2002.....9528.....49101.....243118.....1228036
..8..21..239..1252....9528....59839....413786....2724191....18387032
.13..43..684..4749...49101...413786...3862849...34229311...311423874
.21..85.1909.17285..243118..2724191..34229311..405580157..4951454523
.34.171.5392.64235.1228036.18387032.311423874.4951454523.81304395949

Examples

			Some solutions for n=4 k=4
..1..0..0..0....1..0..0..0....1..0..0..1....1..0..0..0....1..0..0..1
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..0..0....1..0..0..0....0..0..0..0....0..0..0..1....1..0..0..0
..1..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..1..0
		

Crossrefs

Column 1 is A000045
Column 2 is A001045

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +a(n-2)
k=2: a(n) = a(n-1) +2*a(n-2)
k=3: a(n) = 2*a(n-1) +3*a(n-2) -2*a(n-3)
k=4: a(n) = 2*a(n-1) +7*a(n-2) -2*a(n-3) -3*a(n-4)
k=5: a(n) = 2*a(n-1) +16*a(n-2) +a(n-3) -27*a(n-4) +a(n-5) +4*a(n-6)
k=6: [order 8]
k=7: [order 14]