const data = require('./data') const test = (d, i, nr) => { if (i > nr) { let sums = [] for (let a = i - nr - 1; a < i; a++) { for (let b = i - nr - 1; b < i; b++) { if (a !== b) { sums.push(data[a]+data[b]) } } } return sums.indexOf(data[i]) < 0 } else { return false } } const findNr = (nr) => ( data.find((d, i) => { return test(d, i, nr) }) ) console.log(findNr(25))