3,1

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

D. H. and Emma Lehmer, Cyclotomy for nonsquarefree moduli, pp. 276-300 of Analytic Number Theory (Philadelphia 1980), Lect. Notes Math. 899 (1981).

Sequence in context: A027159 A136554 A136505 this_sequence A034792 A135457 A073733

Adjacent sequences: A006308 A006309 A006310 this_sequence A006312 A006313 A006314

nonn

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