A006765 Number of strictly 2-dimensional polyominoes with n cells. (Formerly M3421)

0, 0, 1, 4, 11, 34, 107, 368, 1284, 4654, 17072, 63599, 238590, 901970, 3426575, 13079254, 50107908, 192622051, 742624231, 2870671949, 11123060677, 43191857687, 168047007727, 654999700402, 2557227044763, 9999088822074, 39153010938486, 153511100594602, 602621953061977, 2368347037571251, 9317706529987949, 36695016991712878

Offset

1,4

Comments

A000105 is the main entry for this sequence.

References

Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

John Mason, Table of n, a(n) for n = 1..50 (terms 1..45 from N. J. A. Sloane)

W. F. Lunnon, Counting multidimensional polyominoes. Computer Journal 18 (1975), no. 4, pp. 366-367.

R. C. Schroeppel, A few mathematical experiments, Experimental Mathematics Workshop, Oakland, California, March 30, 2004.

Mathematica

Cases[Import["https://oeis.org/A000105/b000105.txt", "Table"], {_, _}][[All, 2]] - 1 // Rest (* Jean-François Alcover, Jan 21 2020 *)

Crossrefs

Equals A000105(n)-1. A row of A049429. A column of A049430.

Sequence in context: A027045 A243781 A227329 * A151272 A112272 A149234

Adjacent sequences: A006762 A006763 A006764 * A006766 A006767 A006768

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Edited by N. J. A. Sloane, Sep 23 2011

Name clarified by John Mason, Jan 10 2023

Status

approved