A229902 a(n) is the smallest m such that 19*m^k+1 is prime for k=1, 2,...,n.

10, 10, 10, 2080, 178030, 41697270, 4355942080, 1944616927560

Offset: 1

Author

Jahangeer Kholdi, Oct 04 2013

Keywords

• nonn
• more

Comments

10 divides all terms.

Crossrefs

Cf. A106759, A166459, A229906, A229626.

Programs

Mathematica

a[1]=10;a[n_]:=a[n]=(For[m=a[n-1]/10,Union[Table[PrimeQ[19(10m)^k+1],{k,n}]]=={True},m++];10m) (* Farideh Firoozbakht Oct 05 2013 *)

Extensions

a(7) from Farideh Firoozbakht Oct 05 2013

a(8) from Tyler Busby, Jan 06 2023