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A089018 Smallest prime dividing the composite number consisting of A089017(n) successive 3's followed by a terminal 1. 3
17, 673, 307, 19, 523, 607, 181, 199, 31, 1009, 29, 23, 177943, 61, 312929, 17, 821, 353, 363941, 829, 19, 686269, 31, 1019, 2761379, 145501, 1397023, 28529353, 47, 2543, 17, 439, 23, 59, 70717063, 15683, 31, 19, 4555681103, 10616546557, 28759, 83 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..42.

Factordb, (10^n-7)/3

Makoto Kamada, Factorizations of 33...331

PROG

(PARI) do(lim)=my(v=List()); for(n=9, lim+1, if(ispseudoprime(10^n\3-2), next); forprime(p=7, , if(Mod(10, p)^n==7, listput(v, p); next(2)))); Vec(v) \\ tests numbers with A089017(n) <= m; Charles R Greathouse IV, Oct 23 2013

CROSSREFS

Sequence in context: A200907 A203170 A063941 * A118769 A009158 A012050

Adjacent sequences:  A089015 A089016 A089017 * A089019 A089020 A089021

KEYWORD

base,nonn

AUTHOR

Lekraj Beedassy, Nov 04 2003

EXTENSIONS

More terms from Ray Chandler, Nov 04 2003

STATUS

approved

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Last modified June 15 16:13 EDT 2019. Contains 324142 sequences. (Running on oeis4.)