A096058 a(1) = 1, a(n) = largest prime divisor of b(n), where b(1) = 1, b(n) = n*b(n-1) + 1 = A002627(n).

1, 3, 5, 41, 103, 1237, 433, 2389, 2711, 145007, 523, 164611949, 232603841, 201069629, 132267077, 35951249665217, 204405098431, 392881768421, 52255141388393, 8098687, 43894318766250120011, 386270005143001056097

Offset: 1

Author

Amarnath Murthy, Jun 17 2004

Keywords

• nonn

Examples

			a(4) = 41 because b(3) = 3*b(2)+1 = 3*3+1 = 10 and 4*10+1 = 41, which is prime.
b(n) = 1, 3, 10, 41, ... with largest prime divisors a(n) = 1, 3, 5, 41, ...
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..69

Crossrefs

Cf. A096057, A006530, A002627, A096057.

Programs

Mathematica

nxt[{n_,a_}]:={n+1,a(n+1)+1}; FactorInteger[#][[-1,1]]&/@NestList[nxt,{1,1},25][[;;,2]] (* Harvey P. Dale, Jul 22 2024 *)

Formula

a(n) = A006530(A002627(n)).

Extensions

Corrected and extended by Ray G. Opao, Aug 02 2004

Edited by Jonathan Sondow, Jan 09 2005