A118949 Numbers n such that 12345678901098765432*sum(k=1,n,10^(20k-19)) + 1 is prime.

6, 16, 337

Offset

1,1

Comments

The first two terms are given in the linked source in "Table 42: Ten Types of 'Rare' Prime Numbers" for entry "C. Almost-equipandigital prime of the type: (12345678901098765432)n 1", which designates that 12345678901098765432 is concatenated n times and then 1 is appended. 337, found by PrimeForm using recurrence mode, corresponds to a 6741-digit probable prime. There are no other terms <= 3000.

Links

Table of n, a(n) for n=1..3.

R. Ondrejka, The Top Ten: a Catalogue of Primal Configurations

Crossrefs

Cf. A117390.

Sequence in context: A080809 A223098 A290382 * A303213 A264511 A053334

Adjacent sequences: A118946 A118947 A118948 * A118950 A118951 A118952

Keyword

bref,hard,more,nonn

Author

Rick L. Shepherd, May 06 2006

Status

approved