A231796 Count of the first 10^n primes containing at least one 9's digit.

2, 31, 380, 4990, 54268, 581858, 6214940, 67420394, 703398930, 7316745778, 75645891943

Offset: 1

Author

Robert Price, Nov 13 2013

Keywords

• more
• nonn
• base

Examples

			a(2)=31 because there are 31 primes not greater than 541 (the 100th prime) that contain a 9's digit.  Namely: 19, 29, 59, 79, 89, 97, 109, 139, 149, 179, 191, 193, 197, 199, 229, 239, 269, 293, 349, 359, 379, 389, 397, 409, 419, 439, 449, 479, 491, 499, 509.
		

Crossrefs

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

Programs

Mathematica

cnt = 0; Table[Do[p = Prime[k]; If[MemberQ[IntegerDigits[p], 9], 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