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A216551
Numbers n such that (2^n+1)/3 is prime, but cannot be written in the form a^2 + 3*b^2.
0
5, 11, 17, 23, 101, 167, 191, 347, 701, 1709, 3539, 5807, 10691, 11279, 42737, 83339, 95369, 117239, 127031, 267017, 269987, 374321, 4031399
OFFSET
1,1
COMMENTS
The exponent is congruent to 2 mod 3.
CROSSREFS
Cf. A000978.
Sequence in context: A268640 A360542 A214912 * A314255 A369274 A246296
KEYWORD
nonn
AUTHOR
V. Raman, Sep 08 2012
STATUS
approved