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A081317 Primes p such that p divides 10^n-1, p is the largest prime producing decimal fraction period n and p is not the largest prime dividing 10^n-1. 2
13, 52579, 8779, 2161, 69857, 909090909090909091, 459691, 549797184491917, 14175966169, 183411838171, 296557347313446299, 388847808493, 3404193829806058997303, 8985695684401, 297262705009139006771611927 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Ray Chandler, Table of n, a(n) for n = 1..50

Sam Wagstaff, The Cunningham Project, The Main Tables

FORMULA

Numbers in A061075(n) such that A061075(n) is not equal to A005422(n). The corresponding values of n are given in A081318.

EXAMPLE

a(1)=13 because the largest factor 37 in the factorization of 10^6-1=999999=3^3*7*11*13*37 already occurs in the factorization of 10^3-1=3^3*37 and produces only a decimal fraction period of 3. 1/37=0.027027027...., 1/13=0.0769230769230...

CROSSREFS

Cf. A005422, A003020, A061075, A081318.

Sequence in context: A220981 A258670 A048917 * A203675 A189251 A188980

Adjacent sequences:  A081314 A081315 A081316 * A081318 A081319 A081320

KEYWORD

nonn,base

AUTHOR

Hugo Pfoertner, Mar 18 2003

EXTENSIONS

More terms from Hans Havermann, May 31 2003

STATUS

approved

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Last modified July 29 06:21 EDT 2021. Contains 346340 sequences. (Running on oeis4.)