OFFSET
1,1
COMMENTS
Prime digits are 2, 3, 5 or 7.
EXAMPLE
15 is a term: prime(15)=47, and 15 and 47 each have one prime digit.
33 is a term: prime(33)=137, and 33 and 137 each have two prime digits.
39 is a term: prime(39)=167, and 39 and 167 each have two prime digits.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Juri-Stepan Gerasimov, Feb 24 2009
EXTENSIONS
Corrected by R. J. Mathar, Feb 26 2009
Edited by Jon E. Schoenfield, Apr 18 2021
STATUS
approved