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/** This is a solution for the Rosetta Code problem "emirp primes".
An emirp (prime spelled backwards) are primes that when reversed (in their
decimal representation) are a different prime.
(This rules out palindromic primes.)
https://rosettacode.org/wiki/Emirp_primes
*/
isEmirp[x] :=
{
if isPrime[x]
{
s = toString[x]
rev = reverse[s]
return s != rev and isPrime[parseInt[rev]]
}
return false
}
// Functions that return finite and infinite enumerating expressions of emirps
emirps[] := select[primes[], getFunction["isEmirp", 1]]
emirps[begin, end] := select[primes[begin, end], getFunction["isEmirp", 1]]
println["First 20: " + first[emirps[], 20]]
println["Range: " + emirps[7700, 8000]]
println["10000th: " + last[first[emirps[], 10000]]]
Download or view emirp.frink in plain text format
This is a program written in the programming language Frink.
For more information, view the Frink
Documentation or see More Sample Frink Programs.
Alan Eliasen was born 19979 days, 5 hours, 46 minutes ago.