Coding test Euler 6 & 31

Implementations of Project Euler #6 and #31 in R and Julia.

How to run the programs

Julia:

julia julia/euler_6.jl
julia julia/euler_31.jl

or in the REPL:

> include("julia/euler_6.jl")
> include("julia/euler_31.jl")

R:

R -f R/euler_6.R
R -f R/euler_31.R

or in the REPL:

> source("R/euler_6.R")
> source("R/euler_31.R")