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.

A231940 T(n,k)=Number of nXk 0..3 arrays with no element less than a strict majority of its horizontal, diagonal and antidiagonal neighbors.

Original entry on oeis.org

4, 4, 16, 16, 84, 64, 50, 668, 318, 256, 144, 5070, 8426, 1328, 1024, 422, 42104, 206808, 152180, 6064, 4096, 1268, 326010, 4736026, 11159202, 2462572, 26918, 16384, 3823, 2511252, 94464137, 691418144, 518972238, 36885538, 116909, 65536, 11472
Offset: 1

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Author

R. H. Hardin, Nov 15 2013

Keywords

Comments

Table starts
.......4.......4............16...............50................144
......16......84...........668.............5070..............42104
......64.....318..........8426...........206808............4736026
.....256....1328........152180.........11159202..........691418144
....1024....6064.......2462572........518972238........86074040354
....4096...26918......36885538......23280281589.....10417626293694
...16384..116909.....586971925....1098832065447...1320620287047433
...65536..511264....9394148948...52087504055935.167980047970274816
..262144.2248196..147360195020.2432351670277323
.1048576.9868600.2323912599668

Examples

			Some solutions for n=3 k=4
..0..0..0..1....0..0..0..3....2..0..0..2....0..2..2..1....0..0..1..0
..2..0..2..2....3..0..0..3....3..3..0..0....3..0..0..2....2..0..0..3
..2..3..0..0....1..2..3..0....1..0..0..2....2..0..0..0....0..2..3..2
		

Crossrefs

Column 1 is A000302
Column 2 is A231741
Row 1 is A203094 for n>1

Formula

Empirical for column k:
k=1: a(n) = 4*a(n-1)
k=2: [order 19] for n>20
k=3: [order 65] for n>66
Empirical for row n:
n=1: a(n) = 4*a(n-1) -6*a(n-2) +10*a(n-3) -5*a(n-4) +6*a(n-5) -a(n-6) +a(n-7) for n>8
n=2: [order 15]