A140808 a(n) is the smallest composite of the form n*k - 1.

4, 9, 8, 15, 4, 35, 6, 15, 8, 9, 10, 35, 12, 27, 14, 15, 16, 35, 18, 39, 20, 21, 22, 95, 24, 25, 26, 27, 28, 119, 30, 63, 32, 33, 34, 35, 36, 75, 38, 39, 40, 125, 42, 87, 44, 45, 46, 95, 48, 49, 50, 51, 52, 161, 54, 55, 56, 57, 58, 119, 60, 123, 62, 63, 64, 65, 66, 135, 68, 69

Offset

1,1

Links

Table of n, a(n) for n=1..70.

Maple

a:=proc(n) local i: for i while isprime(n*i-1)=true do end do: n*i-1 end proc: 4, 9, seq(a(n), n=3..70); # Emeric Deutsch, Aug 12 2008

Crossrefs

Cf. A061767.

Sequence in context: A179396 A093491 A348512 * A163642 A220533 A357313

Adjacent sequences: A140805 A140806 A140807 * A140809 A140810 A140811

Keyword

nonn

Author

Leroy Quet, Jul 15 2008

Extensions

More terms from Emeric Deutsch, Aug 12 2008

Status

approved