A047875 Size of smallest polyomino with surround number n (the surround number of a polyomino is the number of different ways that it can be surrounded by non-overlapping copies of the same polyomino).

7, 1, 5, 9, 8, 9, 9, 4, 8, 7, 9, 9, 9, 9, 8, 9, 6, 9, 8, 8, 9, 8, 8, 7, 9, 8, 7, 8, 8, 9, 8, 8, 9, 9, 8, 9, 9, 9, 9, 8, 9, 6, 8, 9, 10, 9, 9, 8, 6, 7, 8, 8, 8, 9, 8, 9, 9, 9, 10, 9, 9, 8, 9, 9, 7, 9, 9, 9, 9, 8, 9, 9, 7, 8, 8, 9, 9, 7, 8, 7, 9, 9, 9, 9, 9, 9, 8, 9, 9, 9, 9, 9, 9, 9, 8, 9, 9, 8, 9, 9, 9

Offset

0,1

References

W. F. Lunnon, Counting polyominoes, pp. 347-372 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.

Links

Giovanni Resta, Table of n, a(n) for n = 0..1000 (first 101 terms from Brendan Owen)

E. J. Friedman, Math. Magic

Example

a(2) = 5 because the smallest polyomino which has a surround number 2 is
..X..
.XXX.
..X..

Crossrefs

Cf. A000105.

Sequence in context: A195369 A367710 A348562 * A346610 A064467 A089204

Adjacent sequences: A047872 A047873 A047874 * A047876 A047877 A047878

Keyword

nonn

Author

Brendan Owen (bdowen(AT)ee.mu.oz.au)

Extensions

a(64) corrected by Giovanni Resta, Apr 09 2025

Status

approved