A194596 Number of free polyplets with n cells that are not polyominoes.

0, 1, 3, 17, 82, 489, 2923, 18401, 116848, 753726, 4898579, 32085696, 211398614, 1400292492, 9318028028, 62259251309, 417496576187

Offset

1,3

Links

Table of n, a(n) for n=1..17.

Eric Weisstein's World of Mathematics, Polyplet.

Formula

a(n) = A030222(n) - A000105(n).

Example

XX...X.X..X.. (the 3 for n=3)
..X...X....X.
............X
a(3) = 5 - 2 = 3
a(4) = 22 - 5 = 17
a(5) = 94 - 12 = 82

Crossrefs

Cf. A030222, A000105, A006770 (fixed polyplets), A001168 (fixed polyominoes).

Sequence in context: A202247 A225342 A362390 * A217623 A083217 A225307

Adjacent sequences: A194593 A194594 A194595 * A194597 A194598 A194599

Keyword

nonn,more

Author

Jani Melik, Aug 30 2011

Status

approved