A231790 Count of the first 10^n primes containing at least one 4's digit.

0, 25, 279, 3363, 39395, 485191, 5269618, 56745409, 607655311, 6578438247, 68950399755

Offset: 1

Author

Robert Price, Nov 13 2013

Keywords

• more
• nonn
• base

Examples

			a(2)=25 because there are 25 primes not greater than 541 (the 100th prime) that contain a 4's digit.  Namely: 41, 43, 47, 149, 241, 347, 349, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 541.
		

Crossrefs

Cf. A231726-A231790, A231792-A231796, A091634-A091643, A231412, A228413-A228421.

Programs

Mathematica

cnt = 0; Table[Do[p = Prime[k]; If[MemberQ[IntegerDigits[p], 4], cnt++], {k, 10^(n - 1) + 1, 10^n}]; cnt, {n, 5}] (* T. D. Noe, Nov 13 2013 *)

Formula

a(n) ~ 10^n. - Charles R Greathouse IV, May 21 2014