A062087 Squarefree numbers with all prime digits.

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

Author

Amarnath Murthy, Jun 16 2001

Keywords

• nonn
• base

Comments

Heuristically, there are about 4^n * 275/(48*Pi^2) n-digit terms of this sequence. - Charles R Greathouse IV, Oct 18 2011

Examples

			a(6) = 23, 2 and 3 are both primes.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Intersection of A046034 and A005117.

Programs

Mathematica

Select[Range[3000], Abs[MoebiusMu[#]] == 1 && Union[PrimeQ[IntegerDigits[#]]] == {True} &] (* Alonso del Arte, Oct 18 2011 *)

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 18 2001

Offset corrected by Arkadiusz Wesolowski, Oct 18 2011