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.

A240656 T(n,k)=Number of nXk 0..1 arrays with no element equal to exactly one horizontal or vertical neighbor, with new values 0..1 introduced in row major order.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 3, 9, 3, 1, 1, 6, 17, 17, 6, 1, 1, 10, 43, 91, 43, 10, 1, 1, 21, 136, 352, 352, 136, 21, 1, 1, 42, 402, 1545, 2456, 1545, 402, 42, 1, 1, 86, 1180, 7154, 16629, 16629, 7154, 1180, 86, 1, 1, 179, 3518, 33269, 118863, 184819, 118863, 33269, 3518
Offset: 1

Views

Author

R. H. Hardin, Apr 09 2014

Keywords

Comments

Table starts
.1...1.....1......1........1..........1............1..............1
.1...2.....2......3........6.........10...........21.............42
.1...2.....9.....17.......43........136..........402...........1180
.1...3....17.....91......352.......1545.........7154..........33269
.1...6....43....352.....2456......16629.......118863.........863435
.1..10...136...1545....16629.....184819......2076117.......23697768
.1..21...402...7154...118863....2076117.....37066859......666849212
.1..42..1180..33269...863435...23697768....666849212....18940533171
.1..86..3518.154974..6296517..272201307..12062165754...540011330454
.1.179.10525.724237.46082534.3137010024.218944306666.15442088872458

Examples

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

Crossrefs

Column 2 is A240513(n-2)

Formula

Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 2*a(n-1) +a(n-2) -a(n-3) -2*a(n-4) +a(n-5)
k=3: [order 15]
k=4: [order 50]