A164326 a(n) is the smallest number m such that (2k-1)m - 1 is prime for all 0 < k < n+1.

3, 4, 4, 6, 6, 2100, 2100, 105828450, 3533468190, 240544635660, 7392639784530, 1896344521244250, 5389539504929580, 68086992545221650

Offset

1,1

Links

Table of n, a(n) for n=1..14.

Mathematica

a[n_] := Block[{k=1}, While[! AllTrue[k  Range[1, 2 n - 1, 2] - 1, PrimeQ], k++]; k]; Array[a, 7] (* Giovanni Resta, Apr 01 2017 *)

Crossrefs

Cf. A071576, A164325.

Sequence in context: A120613 A277193 A240728 * A317645 A117571 A008474

Adjacent sequences: A164323 A164324 A164325 * A164327 A164328 A164329

Keyword

more,nonn

Author

Farideh Firoozbakht, Sep 16 2009

Extensions

a(10) from Zak Seidov, Sep 21 2009

a(11)-a(14) from Giovanni Resta, Mar 31 2017

Status

approved