A071808 - OEIS

A071808

Smallest s such that sk+1 is squarefree for 1 <= k <= n.

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

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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 * A355486 A168381 A212621

Adjacent sequences: A071805 A071806 A071807 * A071809 A071810 A071811

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Jun 06 2002

STATUS

approved