Autocorrelation graph for the period. All lags [1..100] (top panel). Prime numbers are shown as squares, other numbers as dots. Prime numbers have higher autocorrelation (positive or negative) as other numbers. The average of absolute AC values for the primes is 0.51 (n = 25), compared to 0.37 (n = 75) for all others. The difference is significant in a t-test with p = 99.8%. The bottom panel shows a zoom into the range of lags [1..25], connecting the integers with dashed lines to show their progression with period-doubling effects.