A107611 Indices of primes with digit product = 2.

1, 47, 318, 10546, 10552, 10629, 86544, 56196114, 56200915, 56676030, 4555804158, 4559732893, 77220966866, 2907021742443997, 2907021767925176, 2907024290266584, 2932496986613869, 51280189662853652, 2461813897281353935, 23422580231698333926, 23422580438055032295

Offset: 1

Author

Zak Seidov, May 17 2005

Keywords

• nonn
• base

Comments

Next term is A000720(111111111111112111) > A000720(10^17) > 2*10^15.

Links

• Kim Walisch, Fast C++ prime counting function implementation (primecount).

Crossrefs

Corresponding primes in A107612.

Cf. A000720, A053666, A101987, A107612.

Programs

Mathematica

Do[If[Apply[Times, IntegerDigits[Prime[n]]]==2, Print[n]], {n, 100000}]

Formula

a(n) = A000720(A107612(n)). - David Wasserman, May 07 2008

Extensions

More terms from Ryan Propper, Jan 03 2008

a(14)-a(21) calculated using Kim Walisch's primecount and added by Amiram Eldar, Sep 03 2024