const fibseries = n => [...Array(n)] .reduce( (fib, _, i) => i < 2 ? ( fib ) : fib.concat(fib[i - 1] + fib[i - 2]), [1, 1] ); const benford = array => [1, 2, 3, 4, 5, 6, 7, 8, 9] .map(val => [val, array .reduce( (sum, item) => sum + ( `${item}` [0] === `${val}` ), 0 ) / array.length, Math.log10(1 + 1 / val) ]); console.log(benford(fibseries(1000)))