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!)
A337385 Odd numbers k for which A003973(k) >= 2*A003961(k). 1
334639305, 1003917915, 1265809545, 1353106755, 1673196525, 2109682575, 2255177925, 2342475135, 2553826275, 2691663975, 2729952225, 2953555605, 2982654675, 3011753745, 3128150025, 3157249095, 3234846615, 3258330075, 3419140725, 3442113675, 3681032355, 3797428635, 3855626775, 4059320265, 4292112825, 4350310965 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Provided that there are no odd perfect numbers, then applying A003961 to each term and sorting into ascending order gives A115414.

Apparently, all terms are divisible by 255255 = 3*5*7*11*13*17. - Hugo Pfoertner, Sep 24 2020

LINKS

Table of n, a(n) for n=1..26.

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

PROG

(PARI)

A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };

isA337385(n) = if(!(n%2), 0, my(x=A003961(n)); (sigma(x)>=2*x));

CROSSREFS

Subsequence of A337386.

Cf. A000203, A003961, A003973, A115414.

Sequence in context: A222978 A353541 A271112 * A233703 A230085 A204337

Adjacent sequences:  A337382 A337383 A337384 * A337386 A337387 A337388

KEYWORD

nonn

AUTHOR

Antti Karttunen, Aug 31 2020

STATUS

approved

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 26 17:16 EDT 2022. Contains 354092 sequences. (Running on oeis4.)