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.

A218838 Unmatched value maps: number of n X 4 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 n X 4 array.

Original entry on oeis.org

7, 57, 453, 3617, 28888, 230726, 1842766, 14717828, 117548611, 938839259, 7498337380, 59887849061, 478313295496, 3820200795065, 30511244937310, 243687732023270, 1946289338913085, 15544656923507264, 124152331330394548
Offset: 1

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Author

R. H. Hardin, Nov 07 2012

Keywords

Comments

Column 4 of A218842.

Examples

			Some solutions for n=3:
..0..0..0..0....1..1..0..0....1..0..0..0....1..1..0..0....1..0..0..1
..1..0..1..1....1..0..0..1....1..0..0..0....1..0..0..0....0..0..1..1
..1..1..0..0....1..0..0..0....0..0..1..1....1..0..1..1....1..1..1..1
		

Crossrefs

Cf. A218842.

Formula

Empirical: a(n) = 7*a(n-1) + 5*a(n-2) + 24*a(n-3) - 9*a(n-4) + 9*a(n-5) for n>6.
Empirical g.f.: x*(7 + 8*x + 19*x^2 - 7*x^3 - x^4 + 3*x^5) / (1 - 7*x - 5*x^2 - 24*x^3 + 9*x^4 - 9*x^5). - Colin Barker, Mar 10 2018