A144326 Prime numbers that cannot be Mersenne prime exponents, by conjecture of A144325.

67, 191, 197, 211, 277, 331, 379, 397, 401, 541, 617, 631, 677, 727, 743, 751, 821, 937, 947, 971, 991, 1129, 1163, 1171, 1217, 1277, 1289, 1327, 1381, 1409, 1427, 1471, 1549, 1559, 1597, 1601, 1607, 1783, 1801, 1831, 1871, 1901, 2011, 2017, 2081, 2111

Offset

1,1

Comments

Obviously true for the initial terms!

Conjecture: 191, 1217, 1559 and 1901 are not in fact members of this sequence, noting that they are (4, 19) k-figurate numbers; 19 is a member of A138694. Determining whether a Mersenne prime exponent one greater than a (4, 19) k-figurate number exists is sufficient to determine whether these primes are members.

Links

Table of n, a(n) for n=1..46.

Crossrefs

Cf. A000040, A000043, A000668, A144313, A144315, A144325, A138694

Sequence in context: A142544 A259888 A142671 * A119593 A142891 A142049

Adjacent sequences: A144323 A144324 A144325 * A144327 A144328 A144329

Keyword

easy,nonn

Author

Reikku Kulon, Sep 17 2008

Status

approved