A093490 a(0) = 2; for n > 0, a(n) is the least prime of the form k*n*a(n-1) - 1.

2, 3, 5, 29, 347, 3469, 41627, 1748333, 27973327, 1007039771, 70492783969, 7754206236589, 2605413295493903, 6503111585552781887, 4825308796480164160153, 1881870430627264022459669

Offset: 0

Author

Amarnath Murthy, Apr 16 2004

Keywords

• nonn

Examples

			a(3) = 29, a(4) = 3*4*29 - 1 = 347.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..200

Crossrefs

Cf. A103342 (corresponding k values), A091771, A091879.

Programs

Mathematica

nxt[{n_,a_}]:=Module[{k=1},While[!PrimeQ[k(n+1)a-1],k++];{n+1, k(n+1)a- 1}]; NestList[nxt,{0,2},20][[All,2]] (* Harvey P. Dale, Feb 27 2020 *)

PARI

v=[2]; for(n=2,20,k=1; while(!isprime(p=k*(n-1)*v[n-1]-1), k++); v=concat(v,p)); v \\ Rick L. Shepherd, Jan 31 2005

Extensions

More terms from Rick L. Shepherd and Ryan Propper, Jan 31 2005

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 14 2007