A096058 - OEIS

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

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..22.

FORMULA

Equals A006530(A002627(n)).

EXAMPLE

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, ...

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 *)

CROSSREFS

Cf. A096057, A006530, A002627, A096057.

Sequence in context: A228968 A178545 A145912 * A120265 A158328 A258933

Adjacent sequences: A096055 A096056 A096057 * A096059 A096060 A096061

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jun 17 2004

EXTENSIONS

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

Edited by Jonathan Sondow, Jan 09 2005

STATUS

approved