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

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A179215 Product of squarefree numbers less than n+1. 7
1, 1, 2, 6, 6, 30, 180, 1260, 1260, 1260, 12600, 138600, 138600, 1801800, 25225200, 378378000, 378378000, 6432426000, 6432426000, 122216094000, 122216094000, 2566537974000, 56463835428000, 1298668214844000, 1298668214844000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

A001221(a(n)) = A000720(n).

Subsequence of A025487.

A034386(n) <= a(n) <= A000142(n).

A179214(n) = a(2*n)/a(n-1) for n>0.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..680

FORMULA

a(n) = PROD(k^A008966(k): 1 <= k <= n).

MATHEMATICA

With[{sfnos=Select[Range[50], SquareFreeQ]}, Table[Times@@Select[sfnos, #<n+1&], {n, 0, 30}]] (* Harvey P. Dale, Jun 13 2011 *)

CROSSREFS

Cf. A013928, A066779, A005117.

Sequence in context: A113461 A061558 A123144 * A069260 A056603 A019198

Adjacent sequences:  A179212 A179213 A179214 * A179216 A179217 A179218

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 05 2010

EXTENSIONS

Definition corrected by Harvey P. Dale, Jun 13 2011

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 12 23:01 EST 2018. Contains 318081 sequences. (Running on oeis4.)