

A153025


Numbers n with property that n and n^2 use only prime digits.


2




OFFSET

1,1


COMMENTS

Probably there are no other terms. No other terms up to 10^40.


LINKS



EXAMPLE

The squares of 5, 235, 72335 are 25, 55225, 5232352225.


MATHEMATICA

Flatten[Table[Select[FromDigits/@Tuples[{2, 3, 5, 7}, n], AllTrue[ IntegerDigits[ #^2], PrimeQ]&], {n, 5}]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Oct 16 2014 *)


CROSSREFS



KEYWORD

nonn,bref,base


AUTHOR



EXTENSIONS



STATUS

approved



