local fmt = require "fmt"

print("The first 61 numbers in the fusc sequence are:")
local fusc = {0, 1}
local fusc2 = {{0, 0}}
local max_len = 1
local n = 2
while n < 20e6 do  -- limit to indices under 20 million say
    local f  = (n % 2  == 0) ? fusc[n/2 + 1] : fusc[(n - 1)/2 + 1] + fusc[(n+1)/2 + 1]
    fusc:insert(f)
    local len = #tostring(f)
    if len > max_len then
        max_len = len
        if n <= 60 then
            fusc2:insert({n, f})
        else
            fmt.print("%10s  %s", fmt.int(n), fmt.int(f))
        end
    end
    if n == 60 then
        for fusc as e do io.write($"{e} ") end
        print("\n\nFirst terms longer than any previous ones for indices < 20,000,000:")
        print("     Index  Value")
        for fusc2 as iv do fmt.print("%10d  %d", iv[1], iv[2]) end
    end
    n += 1
end