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.

A274731 Number of 6Xn 0..2 arrays with no element equal to any value at offset (-1,-2) (-2,-1) or (-1,0) and new values introduced in order 0..2.

Original entry on oeis.org

16, 432, 4132, 52912, 687248, 8960464, 116633012, 1520042284, 19800817976, 257995068564, 3361220228816, 43792711784828, 570555977597820, 7433587136161392, 96849404858071388, 1261816522312628012
Offset: 1

Views

Author

R. H. Hardin, Jul 03 2016

Keywords

Comments

Row 6 of A274728.

Examples

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

Crossrefs

Cf. A274728.

Formula

Empirical: a(n) = 15*a(n-1) +a(n-2) -456*a(n-3) +1455*a(n-4) -196*a(n-5) -5263*a(n-6) +5258*a(n-7) +7193*a(n-8) -12179*a(n-9) -1317*a(n-10) +8177*a(n-11) -894*a(n-12) -2235*a(n-13) +104*a(n-14) +350*a(n-15) +27*a(n-16) -44*a(n-17) +5*a(n-18) for n>20