Calculate primes and factors with caching.
npm install qb-factors
primes(x) returns up to and including the value passed in:
let qbf = require('qb-factors')
qbf.primes(37)
> [ 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37 ]
factors(x) returns prime factors other than 1 and the value passed in:
qbf.factors(37)
> []
qbf.factors(88)
> [ 2, 11 ]