0,2

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

J. Berman, ``Free spectra of 3-element algebras,'' in R. S. Freese and O. C. Garcia, editors, Universal Algebra and Lattice Theory (Puebla, 1982), Lect. Notes Math. Vol. 1004, 1983.

Sequence in context: A090599 A133396 A158981 this_sequence A056410 A056400 A119514

Adjacent sequences: A007151 A007152 A007153 this_sequence A007155 A007156 A007157

nonn

N. J. A. Sloane (njas(AT)research.att.com).