login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A100371 a(n) = 2^phi(n) - 1 = A066781(n) - 1. 7

%I #26 Apr 15 2017 09:32:26

%S 1,1,3,3,15,3,63,15,63,15,1023,15,4095,63,255,255,65535,63,262143,255,

%T 4095,1023,4194303,255,1048575,4095,262143,4095,268435455,255,

%U 1073741823,65535,1048575,65535,16777215,4095,68719476735,262143,16777215,65535

%N a(n) = 2^phi(n) - 1 = A066781(n) - 1.

%C Number of nonempty subsets of reduced residue system [RRS(n)] modulo n.

%H T. D. Noe, <a href="/A100371/b100371.txt">Table of n, a(n) for n = 1..1000</a>

%H N. Bliss, B. Fulan, S. Lovett, and J. Sommars, <a href="http://dx.doi.org/10.4169/amer.math.monthly.120.06.519">Strong Divisibility, Cyclotomic Polynomials, and Iterated Polynomials</a>, Amer. Math. Monthly, 120 (2013), 519-536.

%F a(n) = Sum_{i=1..n} binomial(phi(n), i). - _Enrique PĂ©rez Herrero_, Mar 10 2012

%p A100371:=n->2^numtheory[phi](n)-1: seq(A100371(n), n=1..60); # _Wesley Ivan Hurt_, Apr 14 2017

%t Table[2^EulerPhi[n] - 1, {n, 1, 50}]

%o (PARI) a(n) = 2^eulerphi(n) - 1; \\ _Michel Marcus_, Apr 14 2017

%o (Python)

%o from sympy import totient

%o def a(n): return 2**totient(n) - 1 # _Indranil Ghosh_, Apr 14 2017

%Y Cf. A000010, A066781.

%K easy,nonn

%O 1,3

%A _Labos Elemer_, Nov 30 2004

%E Entry revised by _N. J. A. Sloane_, Jun 07 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)