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.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Reikku Kulon, Sep 17 2008
STATUS
approved