login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071808 Smallest s such that sk+1 is squarefree for 1 <= k <= n. 0
1, 1, 2, 10, 10, 10, 10, 18, 18, 18, 18, 18, 18, 18, 18, 126, 126, 126, 126, 126, 126, 126, 126, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 1470, 1470, 1470, 1890, 1890, 1890, 2310, 2310, 2310, 2310 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n)+1 or a(n)-1 is prime for listed terms.

LINKS

Table of n, a(n) for n=1..53.

PROG

(PARI) for(n=1, 57, s=1; while(sum(i=1, n, issquarefree(s*i+1))<n, s++); print1(s, ", "))

CROSSREFS

Sequence in context: A215463 A066556 A156556 * A168381 A212621 A156780

Adjacent sequences:  A071805 A071806 A071807 * A071809 A071810 A071811

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Jun 06 2002

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 April 14 03:13 EDT 2021. Contains 342941 sequences. (Running on oeis4.)