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Explore Stack Internal1-indexed solution:
#ȯṗdS¤+d←ḣ ḣ -- in the range [1..N] # -- count the number where the following predicate is true ← -- decrement number, S d -- create lists of digits of number and decremented ¤+ -- concatenate, d -- interpret it as number and ȯṗ -- check if it's a prime number Thanks @Zgarb for -3 bytes!
1-indexed solution:
#ȯṗdS¤+d←ḣ ḣ -- in the range [1..N] # -- count the number where the following predicate is true ← -- decrement number, S d -- create lists of digits of number and decremented ¤+ -- concatenate, d -- interpret it as number and ȯṗ -- check if it's a prime number 1-indexed solution:
#ȯṗdS¤+d←ḣ ḣ -- in the range [1..N] # -- count the number where the following predicate is true ← -- decrement number, S d -- create lists of digits of number and decremented ¤+ -- concatenate, d -- interpret it as number and ȯṗ -- check if it's a prime number Thanks @Zgarb for -3 bytes!
1-indexed solution:
£fȯṗdS¤+d←N#ȯṗdS¤+d←ḣ £ ḣ -- Getin the index of input (0 if not exists) inrange [1..N] # f N -- ..allcount naturalthe numbersnumber filteredwhere by: the following predicate is true ← -- decrement number, S d -- create lists of digits of number and decremented ¤+ -- concatenate, d -- interpret it as number and ȯṗ -- check if it's a prime number 1-indexed solution:
£fȯṗdS¤+d←N £ -- Get the index of input (0 if not exists) in .. f N -- ..all natural numbers filtered by: ← -- decrement number, S d -- create lists of digits of number and decremented ¤+ -- concatenate, d -- interpret it as number and ȯṗ -- check if it's a prime number 1-indexed solution:
#ȯṗdS¤+d←ḣ ḣ -- in the range [1..N] # -- count the number where the following predicate is true ← -- decrement number, S d -- create lists of digits of number and decremented ¤+ -- concatenate, d -- interpret it as number and ȯṗ -- check if it's a prime number 1-indexed solution:
£fȯ£İpdS¤+d←N£fȯṗdS¤+d←N £ -- Get the index of input (0 if not exists) in .. f N -- ..all natural numbers filtered by: ← -- decrement number, S d -- create lists of digits of number and decremented number, ¤+ -- concatenate, d -- interpret it as number and ȯ£İp ȯṗ -- check if it's a prime number 1-indexed solution:
£fȯ£İpdS¤+d←N £ -- Get the index of input (0 if not exists) in .. f N -- ..all natural numbers filtered by: ← -- decrement number, S d -- create lists of digits of number and decremented number, ¤+ -- concatenate, d -- interpret it as number and ȯ£İp -- check if it's a prime number 1-indexed solution:
£fȯṗdS¤+d←N £ -- Get the index of input (0 if not exists) in .. f N -- ..all natural numbers filtered by: ← -- decrement number, S d -- create lists of digits of number and decremented ¤+ -- concatenate, d -- interpret it as number and ȯṗ -- check if it's a prime number