A039649 a(n) = phi(n)+1.
2, 2, 3, 3, 5, 3, 7, 5, 7, 5, 11, 5, 13, 7, 9, 9, 17, 7, 19, 9, 13, 11, 23, 9, 21, 13, 19, 13, 29, 9, 31, 17, 21, 17, 25, 13, 37, 19, 25, 17, 41, 13, 43, 21, 25, 23, 47, 17, 43, 21, 33, 25, 53, 19, 41, 25, 37, 29, 59, 17, 61, 31, 37, 33, 49, 21, 67, 33, 45, 25, 71, 25, 73, 37, 41
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..10000
- N. J. A. Sloane, Families of Essentially Identical Sequences, Mar 24 2021 (Includes this sequence)
Programs
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Haskell
a039649 = (+ 1) . a000010 -- Reinhard Zumkeller, Oct 07 2015
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Magma
[EulerPhi(n)+1: n in [1..100]]; // Vincenzo Librandi, Aug 13 2013
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Mathematica
Table[EulerPhi[n] + 1, {n, 100}] (* Vincenzo Librandi, Aug 13 2013 *) -
PARI
a(n)=eulerphi(n)+1 \\ Charles R Greathouse IV, Mar 04 2017
Formula
a(n) = A000010(n) + 1.
a(n) <= n for n > 1.
G.f.: x/(1 - x) + Sum_{k>=1} mu(k)*x^k/(1 - x^k)^2. - Ilya Gutkovskiy, Mar 16 2017
Extensions
Edited by Charles R Greathouse IV, Mar 18 2010.
Comments