OFFSET
1,1
COMMENTS
Prime digit = 2, 3, 5 or 7.
EXAMPLE
2 is a term because 2 is prime, prime(2)=3, and 2 and 3 each have 1 prime digit.
3 is a term because 3 is prime, prime(3)=5, and 3 and 5 each have 1 prime digit.
4 is not a term because 4 is not prime.
5 is prime, but prime(5)=11, and 5 has 1 prime digit while 11 has 0 prime digits, so 5 is not a term.
MAPLE
mm := proc (m) options operator, arrow: convert(m, base, 10) end proc: a := proc (n) local t, s, j: t := 0: s := 0: for j to nops(mm(n)) do if isprime(mm(n)[j]) = true then t := t+1 else end if end do: for j to nops(mm(ithprime(n))) do if isprime(mm(ithprime(n))[j]) = true then s := s+1 else end if end do: if isprime(n) = true and t = s then n else end if end proc: seq(a(n), n = 1 .. 1300); # Emeric Deutsch, Jan 28 2009
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Juri-Stepan Gerasimov, Jan 24 2009
EXTENSIONS
Corrected (added 761, 857; deleted 977) and extended by Emeric Deutsch, Jan 28 2009
Edited by Jon E. Schoenfield, Jan 20 2019
STATUS
approved