A007234 Number of (x -> x^2)-free subsets of symmetric group. (Formerly M3523)

0, 1, 4, 16, 72, 522, 3642, 30753

Offset

1,3

References

P. Bouchard and Y.-N. Yeh, Finding f-free subsets of maximal cardinality, Séries Formelles et Combinatoire Algébrique, 4th colloquium, 15-19 Juin 1992, Montréal, Université du Québec à Montréal, pp. 11-17.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..8.

Crossrefs

Sequence in context: A129872 A059371 A208528 * A096244 A030131 A091530

Adjacent sequences: A007231 A007232 A007233 * A007235 A007236 A007237

Keyword

nonn,more

Author

Simon Plouffe

Status

approved