A219874 Number of tilings of an n X n square using dominoes and straight (3 X 1) trominoes.

1, 0, 2, 14, 184, 9612, 1143834, 354859954, 295743829064, 631206895803116, 3541054185616706122, 51821077154605344550820, 1976225122734369352127065686

Offset

0,3

Links

Table of n, a(n) for n=0..12.

Example

a(3) = 14, because there are 14 tilings of a 3 X 3 square using dominoes and straight (3 X 1) trominoes:
  ._____. ._____. ._____. ._____. .___._. .___._. .___._.
  | | | | | | | | | |___| | |___| | | | | |___| | |___| |
  | | | | | |_|_| | |___| | | | | |_|_| | |___| | | | | |
  |_|_|_| |_|___| |_|___| |_|_|_| |___|_| |___|_| |_|_|_|
  ._____. ._____. ._____. ._____. ._____. ._____. ._____.
  |_____| |_____| |_____| |_____| | |___| | | | | |___| |
  |_____| | |___| | | | | |___| | |_|___| |_|_|_| |___|_|
  |_____| |_|___| |_|_|_| |___|_| |_____| |_____| |_____|  .

Crossrefs

Main diagonal of A219866.

Cf. A233807, A364504.

Sequence in context: A217905 A370940 A237852 * A074655 A268005 A158102

Adjacent sequences: A219871 A219872 A219873 * A219875 A219876 A219877

Keyword

nonn,more

Author

Alois P. Heinz, Nov 30 2012

Extensions

a(12) from Alois P. Heinz, Sep 30 2014

Status

approved