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.

A228390 T(n,k)=Number of nXk binary arrays with top left value 1 and no two ones adjacent horizontally or vertically.

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 3, 5, 5, 3, 5, 12, 21, 12, 5, 8, 29, 72, 72, 29, 8, 13, 70, 268, 382, 268, 70, 13, 21, 169, 963, 2104, 2104, 963, 169, 21, 34, 408, 3513, 11449, 17578, 11449, 3513, 408, 34, 55, 985, 12732, 62546, 143072, 143072, 62546, 12732, 985, 55, 89, 2378
Offset: 1

Views

Author

R. H. Hardin Aug 21 2013

Keywords

Comments

Table starts
..1...1.....2.......3........5..........8...........13............21
..1...2.....5......12.......29.........70..........169...........408
..2...5....21......72......268........963.........3513.........12732
..3..12....72.....382.....2104......11449........62546........341249
..5..29...268....2104....17578.....143072......1177709.......9646285
..8..70...963...11449...143072....1755243.....21683149.....267157140
.13.169..3513...62546..1177709...21683149....402968942....7458864720
.21.408.12732..341249..9646285..267157140...7458864720..207573951234
.34.985.46274.1862631.79185086.3294926929.138305554175.5784184947686

Examples

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

Crossrefs

Column 1 is A000045
Column 2 is A000129

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +a(n-2)
k=2: a(n) = 2*a(n-1) +a(n-2)
k=3: a(n) = 2*a(n-1) +6*a(n-2) -a(n-4)
k=4: a(n) = 4*a(n-1) +9*a(n-2) -5*a(n-3) -4*a(n-4) +a(n-5)
k=5: [order 9]
k=6: [order 11]
k=7: [order 21]