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!)
A324889 a(1) = 1, and for n > 1, a(n) = A276086(n) * a(A064989(n)). 2
1, 3, 18, 9, 324, 15, 3240, 15, 270, 810, 291600, 75, 14580000, 24300, 2250, 225, 6561000000, 1125, 1640250000000, 6750, 607500, 3645000, 3690562500000000, 1875, 337500, 546750000, 56250, 1822500, 41518828125000000000, 105, 581263593750000000000, 21, 1020600, 918540000, 283500, 315, 40688451562500000000000, 688905000000, 765450000, 5670 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(1) = 1, and for n > 1, a(n) = A276086(n) * a(A064989(n)).
A001222(a(n)) = A324890(n).
For all n >= 0, a(A002110(n)) = A002110(1+n)/2.
PROG
(PARI)
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)};
A276086(n) = { my(i=0, m=1, pr=1, nextpr); while((n>0), i=i+1; nextpr = prime(i)*pr; if((n%nextpr), m*=(prime(i)^((n%nextpr)/pr)); n-=(n%nextpr)); pr=nextpr); m; };
A324889(n) = if(1==n, n, A276086(n) * A324889(A064989(n)));
CROSSREFS
Sequence in context: A131635 A324554 A007475 * A281791 A281722 A098874
KEYWORD
nonn
AUTHOR
Antti Karttunen, Mar 30 2019
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 March 28 11:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)