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A116899 Numbers k such that (k concatenated k times) + 1 = A000461(k) + 1 is a prime number. 0
1, 2, 6, 3022 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The (probable) prime corresponding to a(4)=3022, i.e., 3022302230...3023 has 12088 digits. Next term is greater than 5000.

LINKS

Table of n, a(n) for n=1..4.

Primeform: User group for PFGW and PrimeForm programs. [There is insufficient information to determine which posting to the forum was intended. Probably not worth pursuing. - N. J. A. Sloane, Nov 10 2019]

EXAMPLE

1, 2 and 6 are terms since 1+1, 22+1 and 666666+1 are prime numbers.

CROSSREFS

Cf. A000461.

Sequence in context: A140258 A071093 A114045 * A162146 A231545 A055698

Adjacent sequences:  A116896 A116897 A116898 * A116900 A116901 A116902

KEYWORD

base,hard,more,nonn

AUTHOR

Giovanni Resta, Mar 07 2006

STATUS

approved

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Last modified January 21 08:47 EST 2022. Contains 350475 sequences. (Running on oeis4.)