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A199596
a(n) = floor(phi(2*n+1)/phi(2*n+2)).
1
1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 1, 1, 3, 1, 1, 2, 2, 1, 3, 2, 1, 2, 2, 1, 2, 1, 1, 3, 2, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1, 3, 1, 1, 3, 1, 1, 2, 2, 1, 3, 2, 0, 2, 2, 1, 3, 1, 1, 3, 1, 1, 2, 1, 1, 3, 1, 1, 3, 2, 1, 2, 1, 1, 3, 2, 1, 2, 2, 1, 2, 2, 0, 3, 2, 1, 3, 1, 1, 3, 2, 1, 2, 1, 1, 2, 2, 1, 3, 2, 1, 2, 1, 1, 3, 2, 1, 2, 1, 1, 2, 2, 1, 3, 2, 1, 3, 1, 1, 3, 2
OFFSET
0,3
REFERENCES
Dimitris Vathis, Letter to N. J. A. Sloane, Apr 22 1985.
LINKS
MATHEMATICA
Floor[#[[1]]/#[[2]]]&/@Partition[EulerPhi[Range[250]], 2] (* Harvey P. Dale, May 23 2019 *)
PROG
(Magma) [EulerPhi(2*n+1) div EulerPhi(2*n+2): n in [0..100]]; // Vincenzo Librandi, May 24 2019
CROSSREFS
Cf. A000010.
Sequence in context: A249161 A025142 A245936 * A074265 A254688 A002636
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 08 2011
STATUS
approved