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.

A250729 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 min(x(i,j),x(i-1,j)) in the j direction.

Original entry on oeis.org

9, 22, 18, 50, 46, 33, 114, 110, 85, 58, 257, 257, 208, 144, 99, 579, 596, 496, 365, 230, 166, 1302, 1376, 1158, 885, 600, 350, 275, 2927, 3173, 2699, 2092, 1500, 942, 513, 452, 6578, 7310, 6257, 4889, 3605, 2434, 1418, 728, 739, 14782, 16838, 14520, 11377, 8514
Offset: 1

Views

Author

R. H. Hardin, Nov 27 2014

Keywords

Comments

Table starts
....9...22...50...114...257...579...1302...2927....6578...14782...33216
...18...46..110...257...596..1376...3173...7310...16838...38777...89300
...33...85..208...496..1158..2699...6257..14520...33640...77999..180744
...58..144..365...885..2092..4889..11377..26419...61330..142336..330417
...99..230..600..1500..3605..8514..19887..46315..107565..249853..579962
..166..350..942..2434..6016.14437..34069..79704..185684..431691.1002869
..275..513.1418..3807..9728.23941..57397.135645..317769..741367.1725118
..452..728.2065..5760.15297.38821..95231.228455..540546.1268605.2963321
..739.1006.2918..8465.23407.61554.155263.380220..912438.2161980.5081193
.1204.1358.4022.12119.34943.95438.248537.623913.1525255.3661515.8684030

Examples

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

Crossrefs

Column 1 is A192760(n+2)

Formula

Empirical for column k:
k=1: a(n) = 3*a(n-1) -2*a(n-2) -a(n-3) +a(n-4)
k=2: a(n) = 4*a(n-1) -5*a(n-2) +5*a(n-4) -4*a(n-5) +a(n-6); also a polynomial of degree 4 plus a quasipolynomial of degree 0 with period 2
k=3: a(n) = 4*a(n-1) -5*a(n-2) +5*a(n-4) -4*a(n-5) +a(n-6); also a polynomial of degree 4 plus a quasipolynomial of degree 0 with period 2
k=4: a(n) = 5*a(n-1) -9*a(n-2) +5*a(n-3) +5*a(n-4) -9*a(n-5) +5*a(n-6) -a(n-7) for n>8; also a polynomial of degree 5 plus a quasipolynomial of degree 0 with period 2 for n>1
k=5: [order 8; also a polynomial of degree 6 plus a quasipolynomial of degree 0 with period 2] for n>10
k=6: [order 9; also a polynomial of degree 7 plus a quasipolynomial of degree 0 with period 2] for n>14
k=7: [order 10; also a polynomial of degree 8 plus a quasipolynomial of degree 0 with period 2] for n>17
Empirical for row n:
n=1: a(n) = 3*a(n-1) -a(n-2) -2*a(n-3) +a(n-4)
n=2: a(n) = 2*a(n-1) +2*a(n-2) -3*a(n-3) for n>4
n=3: a(n) = 4*a(n-1) -2*a(n-2) -9*a(n-3) +12*a(n-4) -2*a(n-5) -3*a(n-6) +a(n-7) for n>8
n=4: [order 7] for n>9
n=5: [order 9] for n>12
n=6: [order 11] for n>15
n=7: [order 14] for n>19