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A112750 Smallest prime of the form 7 followed by n copies of the digit k, where n runs through those values for which such a prime exists. 0
73, 733, 7333, 79999, 733333, 799999999, 79999999999, 79999999999999999999999999, 79999999999999999999999999999999999999999999999999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Something is wrong here; given the current definition, a(1) should be 71, not 73.

LINKS

Table of n, a(n) for n=1..9.

EXAMPLE

7333 is a term because it is prime and is 7 followed by three copies of 3, and the numbers 7000, 7111, and 7222 are all nonprime.

MATHEMATICA

Select[Quiet[Table[First[Select[FromDigits/@(Prepend[ #, 7]&/@Table[Table[i, {nn}], {i, 3, 9, 2}]), PrimeQ]], {nn, 100}]], NumberQ] (* Harvey P. Dale, Jan 24 2010 *)

CROSSREFS

Subset of A090155.

Sequence in context: A177095 A321422 A133753 * A177514 A137835 A063784

Adjacent sequences:  A112747 A112748 A112749 * A112751 A112752 A112753

KEYWORD

base,nonn,less,uned

AUTHOR

Amarnath Murthy, Jan 02 2006

EXTENSIONS

More terms added by Harvey P. Dale, Jan 24 2010

Name corrected (using a suggestion from Felix Fröhlich) and Example edited by Jon E. Schoenfield, May 28 2019

STATUS

approved

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Last modified November 14 17:24 EST 2019. Contains 329126 sequences. (Running on oeis4.)