Multi-base primes

func max_prime_bases(ndig, maxbase=36) {

    var maxprimebases = [[]]
    var nwithbases = [0]
    var maxprime = (10**ndig - 1)

    for p in (idiv(maxprime + 1, 10) .. maxprime) {
        var dig = p.digits
        var bases = (2..maxbase -> grep {|b| dig.all { _ < b } && dig.digits2num(b).is_prime })
        if (bases.len > maxprimebases.first.len) {
            maxprimebases = [bases]
            nwithbases = [p]
        }
        elsif (bases.len == maxprimebases.first.len) {
            maxprimebases << bases
            nwithbases << p
        }
    }

    var (alen, vlen) = (maxprimebases.first.len, maxprimebases.len)

    say("\nThe maximum number of prime valued bases for base 10 numeric strings of length ",
        ndig, " is #{alen}. The base 10 value list of ", vlen > 1 ? "these" : "this", " is:")
    maxprimebases.each_kv {|k,v| say(nwithbases[k], " => ", v) }
}

for n in (1..5) {
    max_prime_bases(n)
}

Output:

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