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A216449 Numbers n such that the first n digits of the string nnnn... correspond to a prime number. 0
15, 346, 1137, 1429, 11143, 21139 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The primality of the numbers corresponding to the first 4 entries has been certified with Primo.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

n=15 is in the sequence since the 15-digit number 151515151515151 is prime.

MATHEMATICA

f[n_]:=Block[{d=IntegerDigits@n}, FromDigits@d[[Mod[Range@n - 1, Length@d]+1]]]; Select[Range@1500, PrimeQ@f@# &]

CROSSREFS

Subsequence of A171491.

Sequence in context: A286391 A034975 A012787 * A030049 A240375 A202809

Adjacent sequences:  A216446 A216447 A216448 * A216450 A216451 A216452

KEYWORD

nonn,base

AUTHOR

Giovanni Resta, Sep 11 2012

STATUS

approved

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Last modified February 24 10:23 EST 2020. Contains 332209 sequences. (Running on oeis4.)