

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




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 FrÃ¶hlich) and Example edited by Jon E. Schoenfield, May 28 2019


STATUS

approved



