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.

A278627 T(n,k)=Number of nXk 0..2 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake.

Original entry on oeis.org

0, 3, 3, 16, 46, 16, 51, 357, 357, 51, 126, 1952, 4754, 1952, 126, 266, 8518, 49503, 49503, 8518, 266, 504, 31605, 439446, 1069536, 439446, 31605, 504, 882, 103546, 3438414, 21121532, 21121532, 3438414, 103546, 882, 1452, 307087, 24103803
Offset: 1

Views

Author

R. H. Hardin, Nov 24 2016

Keywords

Comments

Table starts
....0......3........16............51..............126.................266
....3.....46.......357..........1952.............8518...............31605
...16....357......4754.........49503...........439446.............3438414
...51...1952.....49503.......1069536.........21121532...........387542112
..126...8518....439446......21121532........978005050.........43853346948
..266..31605...3438414.....387542112......43853346948.......4902306226424
..504.103546..24103803....6594175430....1892563134910.....540194658701142
..882.307087.153073965..103536313036...77595353266488...58237100230743229
.1452.838936.888863183.1496475492375.2984253200734849.6049936223396297740

Examples

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

Crossrefs

Column 1 is A000574(n+1).

Formula

Empirical for column k:
k=1: a(n) = (1/120)*n^5 + (1/8)*n^4 + (5/24)*n^3 - (1/8)*n^2 - (13/60)*n
k=2: [polynomial of degree 15]
k=3: [polynomial of degree 43]
k=4: [polynomial of degree 125]