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.

A197245 Number of nX3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,0,1,1,1 for x=0,1,2,3,4.

Original entry on oeis.org

1, 8, 3, 53, 110, 227, 1035, 2004, 7529, 20633, 53902, 172997, 474139, 1395792, 4009631, 11336881, 33563326, 95906965, 275694011, 796470870, 2294495057, 6647188965, 19110664400, 55033208033, 159018294491, 458707454692
Offset: 1

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Author

R. H. Hardin Oct 12 2011

Keywords

Comments

Every 0 is next to 0 0's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 1's, every 4 is next to 4 1's
Column 3 of A197250

Examples

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

Formula

Empirical: a(n) = a(n-2) +9*a(n-3) +26*a(n-4) +58*a(n-5) -25*a(n-6) -148*a(n-7) -104*a(n-8) -114*a(n-9) +55*a(n-10) -149*a(n-11) +186*a(n-12) -9*a(n-13) +39*a(n-14) -55*a(n-15) +21*a(n-16) +a(n-17) +2*a(n-18) -a(n-19) for n>20