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A062087
Squarefree numbers with all prime digits.
1
2, 3, 5, 7, 22, 23, 33, 35, 37, 53, 55, 57, 73, 77, 222, 223, 227, 233, 235, 237, 253, 255, 257, 273, 277, 322, 323, 327, 335, 337, 353, 355, 357, 373, 377, 523, 527, 533, 535, 537, 553, 555, 557, 573, 577, 723, 727, 733, 737, 753, 755, 757, 773, 777, 2222, 2227
OFFSET
1,1
COMMENTS
Heuristically, there are about 4^n * 275/(48*Pi^2) n-digit terms of this sequence. - Charles R Greathouse IV, Oct 18 2011
LINKS
EXAMPLE
a(6) = 23, 2 and 3 are both primes.
MATHEMATICA
Select[Range[3000], Abs[MoebiusMu[#]] == 1 && Union[PrimeQ[IntegerDigits[#]]] == {True} &] (* Alonso del Arte, Oct 18 2011 *)
CROSSREFS
Intersection of A046034 and A005117.
Sequence in context: A085557 A125665 A046034 * A162457 A084983 A062239
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Jun 16 2001
EXTENSIONS
Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 18 2001
Offset corrected by Arkadiusz Wesolowski, Oct 18 2011
STATUS
approved