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A242824 Primes formed by the initial digits of the decimal expansion of 1/7, starting at the first nonzero digit in the expansion. 4
1428571, 1428571428571428571428571 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Next term has 355 digits.

All terms are of the form 6x+1; a(4) has 823 digits; and there are no further terms up to and including 10000 digits. - Harvey P. Dale, Oct 03 2018

LINKS

Table of n, a(n) for n=1..2.

MATHEMATICA

Select[Table[FromDigits[PadRight[{}, 6n+1, {1, 4, 2, 8, 5, 7}]], {n, 200}], PrimeQ](* Harvey P. Dale, Oct 03 2018 *)

CROSSREFS

Cf. A020806, A241217.

Corresponding sequences for 1/k: A093676 (k=12), A242826 (k=13), A242827 (k=14), A242828 (k=17), A242833 (k=19).

Sequence in context: A301557 A186837 A054852 * A204288 A321040 A234657

Adjacent sequences:  A242821 A242822 A242823 * A242825 A242826 A242827

KEYWORD

nonn,base,bref

AUTHOR

Felix Fröhlich, May 23 2014

STATUS

approved

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Last modified February 28 09:24 EST 2021. Contains 341695 sequences. (Running on oeis4.)