A093948 Primes of the form 9*10^k - 1.

89, 8999, 89999999, 89999999999999999999, 899999999999999999999999999999, 89999999999999999999999999999999999999, 8999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999

Offset

1,1

Comments

Equivalently, primes of the form 8*10^k + 9*R_k, where R_k is the repunit (A002275) of length k.

Links

Table of n, a(n) for n=1..7.

Makoto Kamada, Prime numbers of the form 899...999.

Index entries for primes involving repunits

Crossrefs

Cf. A056725 (corresponding k).

Sequence in context: A264020 A020472 A263431 * A116254 A086695 A056568

Adjacent sequences: A093945 A093946 A093947 * A093949 A093950 A093951

Keyword

nonn

Author

Rick L. Shepherd, Apr 17 2004

Status

approved