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!)
A354821 a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A342001(n/d) * a(d). 2

%I #8 Jun 09 2022 08:45:00

%S 1,-1,-1,-1,-1,-3,-1,0,-1,-5,-1,3,-1,-7,-6,1,-1,4,-1,3,-8,-11,-1,8,-1,

%T -13,0,3,-1,3,-1,1,-12,-17,-10,17,-1,-19,-14,12,-1,1,-1,3,4,-23,-1,3,

%U -1,6,-18,3,-1,8,-14,16,-20,-29,-1,62,-1,-31,4,0,-16,-3,-1,3,-24,-9,-1,-6,-1,-37,6,3,-16,-5,-1,7,1

%N a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A342001(n/d) * a(d).

%C Dirichlet inverse of pointwise sum of A342001 (arithmetic derivative of n / A003557(n)) and A063524 (1, 0, 0, 0, ...).

%H Antti Karttunen, <a href="/A354821/b354821.txt">Table of n, a(n) for n = 1..10080</a>

%H Antti Karttunen, <a href="/A354821/a354821.txt">Data supplement: n, a(n) computed for n = 1..65537</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 A003557(n) = (n/factorback(factorint(n)[, 1]));

%o A342001(n) = (A003415(n) / A003557(n));

%o memoA354821 = Map();

%o A354821(n) = if(1==n,1,my(v); if(mapisdefined(memoA354821,n,&v), v, v = -sumdiv(n,d,if(d<n,A342001(n/d)*A354821(d),0)); mapput(memoA354821,n,v); (v)));

%Y Cf. A003415, A003557, A063524, A342001.

%Y Cf. also A346241.

%K sign

%O 1,6

%A _Antti Karttunen_, Jun 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 July 18 15:13 EDT 2024. Contains 374388 sequences. (Running on oeis4.)