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.

A208780 T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 1 vertically.

Original entry on oeis.org

2, 4, 4, 6, 16, 6, 10, 36, 36, 10, 16, 100, 36, 100, 16, 26, 256, 60, 60, 256, 26, 42, 676, 96, 100, 96, 676, 42, 68, 1764, 156, 160, 160, 156, 1764, 68, 110, 4624, 252, 260, 256, 260, 252, 4624, 110, 178, 12100, 408, 420, 416, 416, 420, 408, 12100, 178, 288, 31684, 660
Offset: 1

Views

Author

R. H. Hardin Mar 01 2012

Keywords

Comments

Table starts
..2....4...6..10...16...26...42...68...110...178...288....466....754....1220
..4...16..36.100..256..676.1764.4624.12100.31684.82944.217156.568516.1488400
..6...36..36..60...96..156..252..408...660..1068..1728...2796...4524....7320
.10..100..60.100..160..260..420..680..1100..1780..2880...4660...7540...12200
.16..256..96.160..256..416..672.1088..1760..2848..4608...7456..12064...19520
.26..676.156.260..416..676.1092.1768..2860..4628..7488..12116..19604...31720
.42.1764.252.420..672.1092.1764.2856..4620..7476.12096..19572..31668...51240
.68.4624.408.680.1088.1768.2856.4624..7480.12104.19584..31688..51272...82960

Examples

			Some solutions for n=4 k=3
..1..0..0....0..1..1....1..1..0....0..1..0....0..1..1....0..1..0....0..1..1
..1..0..1....0..1..0....1..0..0....1..0..0....0..1..1....0..1..1....1..0..1
..0..1..0....1..0..1....0..1..0....0..1..1....1..0..0....1..0..0....0..1..0
..1..0..1....0..1..0....1..0..1....1..0..0....0..1..1....0..1..0....1..0..0
		

Crossrefs

Column 1 is A006355(n+2)
Column 2 is A206981
Diagonal is A206981 and column 2 for n>1
Column 3 is A022346(n+1) for n>2
Column 4 is A022354(n+1) for n>2
Column 5 is A022366(n+1) for n>2

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +a(n-2)
k=2: a(n) = 2*a(n-1) +2*a(n-2) -a(n-3)
k=3: a(n) = a(n-1) +a(n-2) for n>4
k=4: a(n) = a(n-1) +a(n-2) for n>4
k=5: a(n) = a(n-1) +a(n-2) for n>4
k=6: a(n) = a(n-1) +a(n-2) for n>4
k=7: a(n) = a(n-1) +a(n-2) for n>4