login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A130064 (n / SmallestPrimeFactor(n)) * GreatestPrimeFactor(n). 7
1, 2, 3, 4, 5, 9, 7, 8, 9, 25, 11, 18, 13, 49, 25, 16, 17, 27, 19, 50, 49, 121, 23, 36, 25, 169, 27, 98, 29, 75, 31, 32, 121, 289, 49, 54, 37, 361, 169, 100, 41, 147, 43, 242, 75, 529, 47, 72, 49, 125, 289, 338, 53, 81, 121, 196, 361, 841, 59, 150, 61, 961, 147, 64, 169, 363 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = n*A006530(n)/A020639(n) = A032742(n)*A006530(n);

a(n)>=n; a(n)=n iff n is a prime power: a(A000961(n))=A000961(n);

a(A001221(n)) <= A001221(n); a(A001222(n)) = A001222(n);

a(n) = A130065(n)+n*A046665(n)*A074320(n)/A066048(n) = A000290(n)/A130065(n).

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..10000

CROSSREFS

Sequence in context: A241916 A079871 A273291 * A273285 A068795 A222257

Adjacent sequences:  A130061 A130062 A130063 * A130065 A130066 A130067

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 05 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 11 15:43 EST 2017. Contains 295905 sequences.