

A081317


Primes p such that p divides 10^n1, p is the largest prime producing decimal fraction period n and p is not the largest prime dividing 10^n1.


3



13, 52579, 8779, 2161, 69857, 909090909090909091, 459691, 549797184491917, 14175966169, 183411838171, 296557347313446299, 388847808493, 3404193829806058997303, 8985695684401, 297262705009139006771611927
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OFFSET

1,1


LINKS

Max Alekseyev, Table of n, a(n) for n = 1..54 (first 50 terms from Ray Chandler)
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.
a(n) = A061075(A081318(n)).  Max Alekseyev, Apr 27 2022


EXAMPLE

a(1)=13 because the largest factor 37 in the factorization of 10^61=999999=3^3*7*11*13*37 already occurs in the factorization of 10^31=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



