A057418 Number of n-celled free polyominoes with 1 hole.

1, 6, 37, 195, 975, 4622, 21128, 94109, 410820, 1766591, 7506179, 31596240, 131991619, 547992183, 2263477612, 9309386178, 38150082057, 155859235424, 635067478628, 2581737704039, 10474587325120, 42422970467980

Offset

7,2

Links

Table of n, a(n) for n=7..28.

Tomás Oliveira e Silva, Enumeration of polyominoes

Crossrefs

Cf. A001419, A000104, A089454, A089455, A089456, A089457, A089458.

Cf. A057419 (fixed), A057420.

Sequence in context: A056338 A056328 A156185 * A001419 A081152 A244618

Adjacent sequences: A057415 A057416 A057417 * A057419 A057420 A057421

Keyword

nonn,more

Author

N. J. A. Sloane, Sep 05 2000

Extensions

a(27)-a(28) from Tomás Oliveira e Silva's page added by Andrei Zabolotskii, Sep 15 2025

Status

approved