A263958 Prime Riesel numbers p that are not Mersenne primes such that 2*p is a noncototient.

509203, 2554843, 9203917, 9545351, 10645867, 11942443, 14608183, 15627133, 15811777, 16413457, 21013423, 21465637, 25792993, 30622663, 30932729, 32126257, 37996753, 40672237, 41641181, 43099781, 43773809, 47775613, 48400783, 52518187, 52992283

Offset

1,1

Comments

Each of the numbers 2^k*a(n), where k >= 1, is a noncototient.

Links

Table of n, a(n) for n=1..25.

J. Browkin and A. Schinzel, On integers not of the form n - phi(n), Colloq. Math. 68 (1995), pp. 55-58.

A. Flammenkamp and F. Luca, Infinite families of noncototients, Colloq. Math. 86 (2000), pp. 37-41.

Crossrefs

Cf. A005278, A182296.

Sequence in context: A244070 A206430 A182296 * A273987 A250057 A230619

Adjacent sequences: A263955 A263956 A263957 * A263959 A263960 A263961

Keyword

nonn

Author

Arkadiusz Wesolowski, Oct 30 2015

Status

approved