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.

A203980 Number of (n+1) X 5 0..2 arrays with no 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..2 introduced in row major order.

Original entry on oeis.org

384, 5184, 69984, 956448, 13071456, 178855776, 2447270496, 33489653472, 458288894304, 6271519652064, 85823503984224, 1174465206026208, 16072153386090336, 219941927082883296, 3009830115907061856
Offset: 1

Views

Author

R. H. Hardin, Jan 09 2012

Keywords

Comments

Column 4 of A203984.

Examples

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

Crossrefs

Cf. A203984.

Formula

Empirical: a(n) = 15*a(n-1) - 270*a(n-3) + 324*a(n-4).
Empirical g.f.: 96*x*(4 - 6*x - 81*x^2 + 108*x^3) / ((1 - 15*x + 18*x^2)*(1 - 18*x^2)). - Colin Barker, Jun 06 2018