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A097250 Smallest m such that A097249(m) = n; from n=1 onwards, twice the primorials, 2*A002110(n). 6
1, 4, 12, 60, 420, 4620, 60060, 1021020, 19399380, 446185740, 12939386460, 401120980260, 14841476269620, 608500527054420, 26165522663340060, 1229779565176982820, 65178316954380089460, 3845520700308425278140, 234576762718813941966540, 15716643102160534111758180 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A097249(a(n))=n and A097249(m)<n for m<a(n).

a(n) = A088860(n) for n>=1. - G. C. Greubel, Apr 23 2017

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for sequences related to primorial numbers

FORMULA

a(n) = if n=0 then 1 else 2*A002110(n).

MATHEMATICA

Join[{1}, 2 Denominator[Accumulate[1/Prime[Range[20]]]]] (* Vincenzo Librandi, Mar 25 2017 *)

Join[{1}, 2*FoldList[Times, 1, Prime[Range[50]]]] (* G. C. Greubel, Apr 23 2017 *)

CROSSREFS

Cf. A002110, A088860, A097249.

From a(1)=4 onwards, row 3 of A276945.

Sequence in context: A276707 A083484 A088860 * A188328 A291772 A222645

Adjacent sequences:  A097247 A097248 A097249 * A097251 A097252 A097253

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Aug 03 2004

EXTENSIONS

Name amended by Antti Karttunen, Sep 24 2016

a(18)-a(19) from Vincenzo Librandi, Mar 25 2017

STATUS

approved

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Last modified November 27 05:27 EST 2020. Contains 338678 sequences. (Running on oeis4.)