3,2

F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 171.

E. M. Palmer and R. W. Robinson, Enumeration under two representations of the wreath product, Acta Math., 131 (1973), 123-143.

Cf. A003224, A003225.

Adjacent sequences: A003220 A003221 A003222 this_sequence A003224 A003225 A003226

Sequence in context: A022492 A123429 A006841 this_sequence A061417 A060315 A005505

nonn,easy,more

njas