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.

A280069 T(n,k)=Number of nXk 0..1 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 4, 5, 4, 3, 5, 9, 15, 15, 9, 5, 8, 19, 39, 52, 39, 19, 8, 13, 41, 104, 170, 170, 104, 41, 13, 21, 88, 281, 603, 790, 603, 281, 88, 21, 34, 189, 771, 2157, 3729, 3729, 2157, 771, 189, 34, 55, 406, 2122, 7777, 17468, 23564, 17468, 7777, 2122
Offset: 1

Views

Author

R. H. Hardin, Dec 25 2016

Keywords

Comments

Table starts
..1...1....1......2.......3........5.........8..........13...........21
..1...1....2......4.......9.......19........41..........88..........189
..1...2....5.....15......39......104.......281.........771.........2122
..2...4...15.....52.....170......603......2157........7777........28195
..3...9...39....170.....790.....3729.....17468.......82769.......394904
..5..19..104....603....3729....23564....145485......915505......5786757
..8..41..281...2157...17468...145485...1188839.....9934415.....83159859
.13..88..771...7777...82769...915505...9934415...110266512...1225662273
.21.189.2122..28195..394904..5786757..83159859..1225662273..18113056960
.34.406.5858.102429.1890877.36671797.698377561.13669391105.268403179093

Examples

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

Crossrefs

Column 1 is A000045(n-1).
Column 2 is A078039(n-2).

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +a(n-2) for n>3
k=2: a(n) = a(n-1) +2*a(n-2) +a(n-3) for n>4
k=3: a(n) = 3*a(n-1) +a(n-2) -6*a(n-3) +5*a(n-4) -2*a(n-5) -2*a(n-6) -a(n-7) for n>9
k=4: [order 15] for n>18
k=5: [order 35] for n>40
k=6: [order 87] for n>91