A166755 Number of n X n 1..2 arrays containing at least one of each value, and all equal values connected.

0, 12, 106, 1254, 32426, 2247486, 443968782, 255122769986, 431534126902662, 2165656440779563158, 32418178732724142833570, 1452876796004423753334759362, 195482230310004930545348833858390, 79131192890976439895988807925969458614, 96533107106359142781127117074385161767893162

Offset: 1

Author

R. H. Hardin, Oct 21 2009

Keywords

• nonn

Examples

			Some solutions for n=4
...1.2.2.2...1.1.1.1...2.2.2.1...2.1.1.1...1.1.1.1...2.2.2.2...1.1.1.2
...1.2.1.2...2.2.2.1...2.2.2.1...2.2.1.1...1.1.2.2...1.2.2.2...2.2.1.2
...1.1.1.2...2.2.2.1...2.2.1.1...1.1.1.1...1.1.2.2...2.2.2.2...2.1.1.2
...2.2.2.2...2.1.1.1...2.2.2.2...1.1.1.1...2.2.2.2...2.2.2.2...2.2.2.2
------
...1.1.1.2...2.1.1.1...2.2.2.2...1.1.1.1...1.1.1.1...1.1.1.1...2.2.2.2
...1.1.2.2...2.1.1.1...2.2.1.2...1.1.1.1...2.2.1.1...1.2.1.2...1.2.2.2
...1.1.1.2...2.2.1.1...2.2.1.2...1.1.2.1...1.2.1.1...1.2.2.2...1.1.2.2
...1.1.2.2...2.2.2.2...2.1.1.1...2.2.2.1...1.1.1.1...1.1.1.2...1.1.1.2
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..26

Crossrefs

Cf. A068416.

Formula

a(n) = 2*A068416(n). - Andrew Howroyd, Dec 11 2024

Extensions

a(7) onwards added using A068416 by Andrew Howroyd, Dec 11 2024