A199596 a(n) = floor(phi(2*n+1)/phi(2*n+2)).

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

Harvey P. Dale, Table of n, a(n) for n = 0..1000

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

Adjacent sequences: A199593 A199594 A199595 * A199597 A199598 A199599

Keyword

nonn

Author

N. J. A. Sloane, Nov 08 2011

Status

approved