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%I #3 Mar 31 2012 10:28:53
%S 67,191,197,211,277,331,379,397,401,541,617,631,677,727,743,751,821,
%T 937,947,971,991,1129,1163,1171,1217,1277,1289,1327,1381,1409,1427,
%U 1471,1549,1559,1597,1601,1607,1783,1801,1831,1871,1901,2011,2017,2081,2111
%N Prime numbers that cannot be Mersenne prime exponents, by conjecture of A144325.
%C Obviously true for the initial terms!
%C 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.
%Y Cf. A000040, A000043, A000668, A144313, A144315, A144325, A138694
%K easy,nonn
%O 1,1
%A _Reikku Kulon_, Sep 17 2008