A281958 Primes p such that p^2 - 1 is not a totient number (A002202).

2, 173, 317, 509, 709, 773, 787, 947, 1307, 1447, 1579, 1613, 1627, 1867, 2347, 2467, 2693, 3307, 3413, 3547, 3803, 3923, 4007, 4243, 4567, 4597, 4723, 4793, 4813, 4937, 4973, 5227, 5261, 5387, 5483, 5557, 5653, 5717, 5827, 5843, 6277, 6397, 6547, 6653, 6793, 6907

Offset

1,1

Comments

Corresponding values of p^2 - 1 are 3, 29928, 100488, 259080, 502680, 597528, 619368, 896808, 1708248, ...

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Example

Prime number 173 is a term because 173^2 - 1 = 29928 is not a totient number.

Prog

(PARI) is(n) = isprime(n) && !istotient(n^2-1);

Crossrefs

Cf. A000010, A002202, A007617, A084920.

Sequence in context: A339641 A262728 A139935 * A172231 A360478 A193638

Adjacent sequences: A281955 A281956 A281957 * A281959 A281960 A281961

Keyword

nonn

Author

Altug Alkan, Feb 03 2017

Status

approved