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
Keywords
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
Programs
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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 *)
Extensions
Corrected and extended by Ray G. Opao, Aug 02 2004
Edited by Jonathan Sondow, Jan 09 2005