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.

A250783 T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

Original entry on oeis.org

9, 21, 18, 46, 46, 36, 99, 106, 96, 72, 209, 238, 230, 196, 144, 436, 518, 534, 482, 396, 288, 901, 1106, 1194, 1152, 990, 796, 576, 1849, 2326, 2604, 2640, 2426, 2010, 1596, 1152, 3774, 4838, 5568, 5882, 5688, 5028, 4054, 3196, 2304, 7671, 9978, 11732, 12796
Offset: 1

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Author

R. H. Hardin, Nov 27 2014

Keywords

Comments

Table starts
....9....21....46....99....209....436.....901....1849....3774.....7671....15541
...18....46...106...238....518...1106....2326....4838....9978....20446....41686
...36....96...230...534...1194...2604....5568...11732...24442....50482...103566
...72...196...482..1152...2640...5882...12796...27344...57610...120060...248072
..144...396...990..2426...5688..12950...28692...62274..132890...279864...583196
..288...796..2010..5028..12036..27986...63184..139436..301786...643164..1353544
..576..1596..4054.10306..25126..59590..137082..307762..676266..1460260..3107536
.1152..3196..8146.20960..51904.125334..293588..670608.1496970..3278004..7061504
.2304..6396.16334.42394.106344.260916..621664.1444162.3275574..7278104.15884220
.4608.12796.32714.85420.216500.538538.1303276.3076788.7089558.15987988.35370676

Examples

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

Crossrefs

Column 1 is A005010(n-1)
Row 1 is A027973(n+1)

Formula

Empirical for column k:
k=1: a(n) = 2*a(n-1); a(n) = 9*2^(n-1)
k=2: a(n) = 3*a(n-1) -2*a(n-2); a(n) = 25*2^(n-1) -4
k=3: a(n) = 4*a(n-1) -5*a(n-2) +2*a(n-3)
k=4: a(n) = 6*a(n-1) -14*a(n-2) +16*a(n-3) -9*a(n-4) +2*a(n-5)
k=5: a(n) = 8*a(n-1) -27*a(n-2) +50*a(n-3) -55*a(n-4) +36*a(n-5) -13*a(n-6) +2*a(n-7)
k=6: [order 9]
k=7: [order 11]
Empirical for row n:
n=1: a(n) = 3*a(n-1) -a(n-2) -2*a(n-3)
n=2: a(n) = 4*a(n-1) -4*a(n-2) -a(n-3) +2*a(n-4)
n=3: a(n) = 5*a(n-1) -8*a(n-2) +3*a(n-3) +3*a(n-4) -2*a(n-5)
n=4: a(n) = 5*a(n-1) -7*a(n-2) -2*a(n-3) +11*a(n-4) -5*a(n-5) -3*a(n-6) +2*a(n-7)
n=5: [order 8]
n=6: [order 9]
n=7: [order 10]