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A217035
Generalized cuban primes (A007645) which are also Class 1- (or Pierpont) primes (A005109).
2
3, 7, 13, 19, 37, 73, 97, 109, 163, 193, 433, 487, 577, 769, 1153, 1297, 1459, 2593, 2917, 3457, 3889, 10369, 12289, 17497, 18433, 39367, 52489, 139969, 147457, 209953, 331777, 472393, 629857, 746497, 786433, 839809, 995329, 1179649, 1492993, 1769473
OFFSET
1,1
COMMENTS
Is this the union of A058383 and {3}? - R. J. Mathar, Sep 28 2012
Yes, it is, because the only Fermat prime == 0 or 1 mod 3 is 3. - Robert Israel, Mar 02 2018
Generalized cuban primes are primes of the form x^2 + xy + y^2; or: primes of form x^2 + 3*y^2; or: primes == 0 or 1 mod 3. Class 1- (or Pierpont) primes: primes of the form 2^t*3^u + 1.
LINKS
Ray Chandler, Table of n, a(n) for n = 1..8379 (terms < 10^1000)
FORMULA
A007645 INTERSECTION A005109.
MATHEMATICA
nn = 100000; t1 = Join[{3}, Select[Prime[Range[nn]], MemberQ[{1}, Mod[#, 3]] &]]; t2 = Select[Prime[Range[nn]], Max @@ First /@ FactorInteger[# - 1] < 5 &]; Intersection[t1, t2] (* T. D. Noe, Sep 26 2012 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jonathan Vos Post, Sep 24 2012
STATUS
approved