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a(n)-th prime is the smallest prime containing exactly n 7's.
1

%I #13 Apr 03 2023 10:36:09

%S 1,4,59,275,4924,58623,506877,4546755,30224014,87818618,2836649805,

%T 14748299309,251285857122,603200604933

%N a(n)-th prime is the smallest prime containing exactly n 7's.

%H Andrew R. Booker, <a href="https://t5k.org/nthprime/">The Nth Prime Page</a>

%t (* see A037067 for f *) PrimePi[ Table[ f[n, 7], {n, 1, 12}]]

%Y Cf. A037067, A034388.

%K nonn,base,hard

%O 0,2

%A _Patrick De Geest_, Jan 04 1999

%E a(0)=1 prepended by _Sean A. Irvine_, Dec 06 2020