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EXAMPLE
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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.
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MATHEMATICA
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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 *)
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