A078814 Smallest prime factor of Googolplex - n which exceeds 16.

17, 1433, 499679, 1279, 31, 149

Offset

1,1

Comments

Seventh term is not known. Sequence continues ?, 625392489737, 19, 37, 5419, 107, 23, 60149, 1733, 89, 8543, 17, 5261, 229, 8656871, 4273, 14009, 29, 509, 43628661784403, 24539783, 19, 347, 12414692011, 523, 151, 421, 35816135619181, 17, 23, 184309, ?, 181, 288481, 163, 41, 743, 13337, 71, 53, 19, 59, 113, 37957721, ... where the unknown numbers exceed 25 * 10^12. - Dario Alpern, Jul 03 2003

Links

Table of n, a(n) for n=1..6.

Dario Alejandro Alpern, Factors of 1000 numbers up to googolplex.

Mathematica

(* For any individual n *) k = 17; While[ !PrimeQ[k] || PowerMod[10, 10^100, k] - n != 0, k += 2]; k

Prog

(PARI) a(n) = forprime(p=17, oo, if(Mod(10, p)^lift(Mod(10, p-1)^100) == n, return(p))); \\ Jinyuan Wang, Apr 17 2020

Crossrefs

Cf. A072288.

Sequence in context: A256020 A072160 A376097 * A242282 A129911 A336196

Adjacent sequences: A078811 A078812 A078813 * A078815 A078816 A078817

Keyword

nonn,hard,more,fini

Author

Ed Pegg Jr and Robert G. Wilson v, Dec 06 2002

Status

approved