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

1,2

Links

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

Formula

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

Example

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

Crossrefs

Cf. A068416.

Sequence in context: A144133 A089396 A218111 * A230712 A271559 A154671

Adjacent sequences: A166752 A166753 A166754 * A166756 A166757 A166758

Keyword

nonn,changed

Author

R. H. Hardin, Oct 21 2009

Extensions

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

Status

approved