The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A353753 a(n) = phi(sigma(n)) - Product_{p^e||n} phi(sigma(p^e)), where n = Product_{p^e||n}, with each p^e the maximal power of prime p that divides n. 8

%I #10 May 08 2022 15:39:31

%S 0,0,0,0,0,0,0,0,0,2,0,0,0,0,4,0,0,0,0,0,8,4,0,0,0,0,0,0,0,16,0,0,8,6,

%T 8,0,0,0,12,8,0,16,0,0,0,8,0,0,0,0,12,6,0,0,16,0,16,8,0,24,0,0,0,0,12,

%U 32,0,0,16,32,0,0,0,0,0,0,16,24,0,0,0,12,0,48,24,0,16,16,0,24,24,0,32,16,16,0,0,36

%N a(n) = phi(sigma(n)) - Product_{p^e||n} phi(sigma(p^e)), where n = Product_{p^e||n}, with each p^e the maximal power of prime p that divides n.

%H Antti Karttunen, <a href="/A353753/b353753.txt">Table of n, a(n) for n = 1..65537</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%F a(n) = A062401(n) - A353752(n).

%o (PARI)

%o A062401(n) = eulerphi(sigma(n));

%o A353753(n) = { my(f = factor(n)); A062401(n)-prod(k=1, #f~, A062401(f[k, 1]^f[k, 2])); };

%Y Cf. A000010, A000203, A062401, A353752, A353754, A353755.

%Y Cf. A336547 (positions of 0's), A336548 (positions of terms > 0).

%Y Cf. also A353803.

%K nonn

%O 1,10

%A _Antti Karttunen_, May 08 2022

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 May 21 22:16 EDT 2024. Contains 372741 sequences. (Running on oeis4.)