S001025


Smaller twin prime p such that phi(p-1) <= phi(p+1), where phi is Euler’s totient function.

3, 5, 11, 71, 2381, 2591, 3851, 14561, 17291, 20021, 20231, 26951, 34511, 41231, 47741, 50051, 52361, 55931, 57191, 65171, 67211, 67271, 70841, 82811, 87011, 98561, 101501, 101531, 108461, 117041, 119771, 126491, 129221, 134681, 136991, 142871, 145601, 150221

1

S001025

This is the union of S001022 and S001023.

T. D. Noe, Plot of 1005 terms

T. D. Noe, Table of 1005 terms

Stephan Ramon Garcia, Elvis Kahoro, and Florian Luca, Primitive root discrepancy for twin primes, arXiv 1705.02485 (May 06 2017)

(Mma) t = {}; n = 0; While[Length[t] < 100, n++; p = Prime[n]; If[PrimeQ[p + 2] && EulerPhi[p - 1] <= EulerPhi[p + 1], AppendTo[t, p]]]; t

Cf. S001021-S001024.

nonn

T. D. Noe, May 10 2017

© Tony D Noe 2014-2017