7,3
Tomas Oliveira e Silva, Enumeration of polyominoes
Sequence in context: A133167 A133173 A070374 * A204930 A167636 A180137
Adjacent sequences: A057420 A057421 A057422 * A057424 A057425 A057426
nonn
N. J. A. Sloane (njas(AT)research.att.com), Sep 05 2000