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 A185278 Number of isomorphism classes of generalized Petersen graphs G(n,k) on 2n vertices with gcd(n,k) = 1. 1
 1, 1, 2, 1, 2, 2, 2, 2, 3, 2, 4, 2, 3, 3, 5, 2, 5, 3, 4, 3, 6, 4, 6, 4, 5, 4, 8, 3, 8, 5, 6, 5, 7, 4, 10, 5, 7, 6, 11, 4, 11, 6, 7, 6, 12, 6, 11, 6, 9, 7, 14, 5, 11, 8, 10, 8, 15, 6, 16, 8, 10, 9, 14, 6, 17, 9, 12, 7, 18, 8, 19, 10, 11, 10, 16, 7, 20, 10, 14, 11, 21, 8, 18, 11, 15, 12, 23, 7, 19, 12, 16, 12, 19, 10, 25, 11, 16, 11 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,3 LINKS Robert Israel, Table of n, a(n) for n = 3..10000 Marko Petkovsek and Helena Zakrajsek, Enumeration of I-graphs: Burnside does it again, Ars Mathematica Contemporanea, 2 (2009) 241-262. A. Steimle and W. Staton, The isomorphism classes of the generalized Petersen graphs, Discrete Math. 309 (2009), 231-237. FORMULA a(n) = (A000010(n) + A060594(n) + A000089(n))/4. MAPLE # using functions A060594 and A000089 as defined in those sequences f:= n -> (numtheory:-phi(n)+A060594(n)+A000089(n))/4: map(f, [\$3..100]); # Robert Israel, Sep 06 2018 CROSSREFS Cf. A000010, A000089, A060594. Sequence in context: A320385 A112222 A112220 * A241065 A086376 A160089 Adjacent sequences:  A185275 A185276 A185277 * A185279 A185280 A185281 KEYWORD nonn,look AUTHOR N. J. A. Sloane, Feb 19 2011 STATUS approved

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Last modified May 6 00:41 EDT 2021. Contains 343579 sequences. (Running on oeis4.)