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

Author

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

Keywords

• nonn

Examples

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

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

Crossrefs

Cf. A000105.

Extensions

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