#Japt, 15 14 12 11 9 8 bytes 1-indexed.

ÇsiZÄÃèj 

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Ç :Map each Z in the range [0,input) s : Convert to string i : Prepend ZÄ : Z+1 Ã :End map è :Count j : Primes 

Japt, 15 14 12 11 9 8 bytes

1-indexed.

ÇsiZÄÃèj 

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Ç :Map each Z in the range [0,input) s : Convert to string i : Prepend ZÄ : Z+1 Ã :End map è :Count j : Primes 

#Japt, 15 14 12 11 9 8 bytes 1-indexed.

ÇsiZÄÃèj 

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Ç :Map each X in the range [0,input) s : Convert to string i : Prepend ZÄ : Z+1 Ã :End map è :Count j : Primes 

#Japt, 15 14 12 11 9 8 bytes 1-indexed.

ÇsiZÄÃèj 

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Ç :Map each Z in the range [0,input) s : Convert to string i : Prepend ZÄ : Z+1 Ã :End map è :Count j : Primes 

#Japt, 15 14 12 11 9 bytes 1-indexed.

Çs_i°Z èj 

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##Explanation Ç :Create the range [0,input) and pass each through a function s_ : Convert to a string, pass it through a function and convert back to an integer i : Prepend °Z : The prefix incremented string èj :Count the primes

##Original Solution

1 byte saved thanks to Oliver

Æ[XÄX]¬nÃèj 

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Æ Ã :Create the range [0,input) and pass each X through a function [XÄX] : Array [X+1,X] ¬ : Join to a string  n : Convert to an integer   èj :Count the primes 

#Japt, 15 14 12 11 9 8 bytes 1-indexed.

ÇsiZÄÃèj 

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Ç :Map each X in the range [0,input)   s  : Convert to string i  :  Prepend ZÄ : Z+1  Ã :End map  è :Count j : Primes