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!)
A358215 Numbers k for which there is no prime p such that p^p divides the arithmetic derivative of k, A003415(k). 7

%I #21 Feb 22 2024 20:08:24

%S 2,3,5,6,7,9,10,11,13,14,17,18,19,21,22,23,25,26,29,30,31,33,34,37,38,

%T 41,42,43,45,46,47,49,50,53,57,58,59,61,62,63,65,66,67,69,70,71,73,74,

%U 75,77,78,79,82,83,85,86,89,90,93,94,97,98,99,101,102,103,105,106,107,109,110,113,114,117,118,121,122,125

%N Numbers k for which there is no prime p such that p^p divides the arithmetic derivative of k, A003415(k).

%C Numbers k such that A003415(k) is in A048103.

%H Antti Karttunen, <a href="/A358215/b358215.txt">Table of n, a(n) for n = 1..10000</a>

%o (PARI)

%o A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));

%o A359550(n) = { my(f = factor(n)); prod(k=1, #f~, (f[k, 2]<f[k, 1])); };

%o A368915(n) = ((n>1)&&A359550(A003415(n)));

%o isA358215(n) = A368915(n);

%Y Complement of {1} U A327929. Positions of 0's in A341996 (after the two initial zeros). Positions of 1's in A341997.

%Y Subsequence of A048103.

%Y Subsequences: A099308 (apart from its two initial terms), A328393, A358221.

%Y Cf. A003415, A327934, A351088, A359550, A368915 (characteristic function).

%K nonn

%O 1,1

%A _Antti Karttunen_, Nov 24 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 September 4 22:02 EDT 2024. Contains 375685 sequences. (Running on oeis4.)