experimental-projects/oeis-research/Falcon Shapiro/Smallest number that requires at least n repdigits (not necessary distinct) to sum/prog.sf

#!/usr/bin/ruby

# a(n) is the smallest number that requires at least n repdigits (not necessary distinct) to sum.
# https://oeis.org/A336748

# Known terms:
#   1, 10, 21, 320, 2219, 32218, 332217, 3332216, 33332215

var n = 6
var limit = 32218

var arr = []

for k in (1..9) {
    for j in (1..limit.len) {
        arr << Num("#{k}"*j)
    }
}

arr = arr.grep { _ < limit }.uniq.sort

var seen = Hash()

for k in (1..n) {
    arr.combinations_with_repetition(k, {|*a|
        var t = a.sum

        if (seen.has(t)) {
            seen{t} = k if (k < seen{t})
        }
        else {
            seen{t} = k
        }
    })
}

var z = seen.grep_v{ _ == n }.keys.map{.to_n}.min

say [z, seen{z}]