A089018 Smallest prime dividing the composite number consisting of A089017(n) successive 3's followed by a terminal 1.

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

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: A203170 A350981 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