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Total number of 4's digits in primes less than 10^n.
0

%I #14 Jun 16 2019 13:31:12

%S 0,3,34,360,3772,39006,397474,4022501,40604951,408986159,4113511677,

%T 41331763006,414971464358,4163826451096

%N Total number of 4's digits in primes less than 10^n.

%e a(2)=3, since there are 3 4's in primes less than 100. Namely: 41, 43, 47.

%t Table[Count[IntegerDigits[Prime[Range[PrimePi[10^n - 1]]]], 4, 2], {n, 7}] (* _Robert Price_, Jun 16 2019 *)

%Y Cf. A231411, A231590-A231598, A119290, A119291-A119300.

%K nonn,base,more

%O 1,2

%A _Robert Price_, Nov 11 2013

%E a(14) from _Giovanni Resta_, Jul 20 2015