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.

A263597 T(n,k)=Number of length n arrays of permutations of 0..n-1 with each element moved by -k to k places and the median of every three consecutive elements nondecreasing.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 2, 6, 5, 1, 2, 6, 12, 8, 1, 2, 6, 16, 25, 13, 1, 2, 6, 16, 41, 57, 21, 1, 2, 6, 16, 52, 108, 124, 34, 1, 2, 6, 16, 52, 164, 280, 268, 55, 1, 2, 6, 16, 52, 208, 476, 729, 588, 89, 1, 2, 6, 16, 52, 208, 676, 1428, 1908, 1285, 144, 1, 2, 6, 16, 52, 208, 800, 2208, 4308
Offset: 1

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Author

R. H. Hardin, Oct 22 2015

Keywords

Comments

Table starts
..1....1....1.....1.....1.....1.....1.....1.....1.....1.....1.....1.....1.....1
..2....2....2.....2.....2.....2.....2.....2.....2.....2.....2.....2.....2.....2
..3....6....6.....6.....6.....6.....6.....6.....6.....6.....6.....6.....6.....6
..5...12...16....16....16....16....16....16....16....16....16....16....16....16
..8...25...41....52....52....52....52....52....52....52....52....52....52....52
.13...57..108...164...208...208...208...208...208...208...208...208...208...208
.21..124..280...476...676...800...800...800...800...800...800...800...800...800
.34..268..729..1428..2208..2900..3360..3360..3360..3360..3360..3360..3360..3360
.55..588.1908..4308..7696.10960.14024.16224.16224.16224.16224.16224.16224.16224
.89.1285.4969.12816.25508.40792.55492.69212.78088.78088.78088.78088.78088.78088

Examples

			Some solutions for n=6 k=4
..1....1....1....0....2....0....0....0....1....4....3....2....1....4....0....2
..2....2....0....1....1....5....3....1....5....1....1....0....4....0....1....0
..3....3....2....3....5....2....2....2....0....0....0....1....0....1....3....1
..0....0....4....4....3....3....1....5....2....2....2....5....3....3....5....3
..4....5....3....2....0....4....4....3....4....3....4....3....5....2....2....4
..5....4....5....5....4....1....5....4....3....5....5....4....2....5....4....5
		

Crossrefs

Column 1 is A000045(n+1).
Column 2 is A214663.

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +a(n-2)
k=2: a(n) = a(n-1) +a(n-2) +3*a(n-3) +a(n-4)
k=3: a(n) = a(n-1) +a(n-2) +7*a(n-3) +2*a(n-4) +4*a(n-5) -a(n-7) -a(n-8)
k=4: [order 15]
k=5: [order 31]
k=6: [order 67]