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!)
A319525 Completely multiplicative with a(prime(k)) = prime(2*k - 1) (where prime(k) denotes the k-th prime). 3

%I #8 Aug 11 2022 09:57:38

%S 1,2,5,4,11,10,17,8,25,22,23,20,31,34,55,16,41,50,47,44,85,46,59,40,

%T 121,62,125,68,67,110,73,32,115,82,187,100,83,94,155,88,97,170,103,92,

%U 275,118,109,80,289,242,205,124,127,250,253,136,235,134,137,220

%N Completely multiplicative with a(prime(k)) = prime(2*k - 1) (where prime(k) denotes the k-th prime).

%C This sequence is a permutation of A066208.

%C See A297002 for a similar sequence.

%F a(n) = A064989(A297002(n)).

%F a(n) >= n with equality iff n is a power of 2 (A000079).

%o (PARI) a(n) = my (f=factor(n)); prod(i=1, #f~, prime(2*primepi(f[i, 1]) - 1)^f[i, 2])

%Y Cf. A000079, A066208, A297002.

%K nonn,mult

%O 1,2

%A _Rémy Sigrist_, Sep 22 2018

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 April 19 12:14 EDT 2024. Contains 371792 sequences. (Running on oeis4.)