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A118949
Numbers n such that 12345678901098765432*sum(k=1,n,10^(20k-19)) + 1 is prime.
0
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.
CROSSREFS
Cf. A117390.
Sequence in context: A080809 A223098 A290382 * A303213 A264511 A053334
KEYWORD
bref,hard,more,nonn
AUTHOR
Rick L. Shepherd, May 06 2006
STATUS
approved