

A183075


Numbers of the form 2^k  1 for which each prime divisor has the form 4j + 3.


8



1, 3, 7, 31, 63, 127, 1023, 8191, 16383, 32767, 131071, 524287, 67108863, 1073741823, 2147483647, 17179869183, 274877906943, 8796093022207, 2251799813685247, 2305843009213693951
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OFFSET

1,2


COMMENTS

The Mersenne primes (A000668) are contained in this sequence.
Needed factorizations are in the Cunningham Project.


LINKS



FORMULA



EXAMPLE

63 = 2^6  1 = 3^2 * 7, and 3 and 7 have the form 4j + 3.


CROSSREFS



KEYWORD

nonn,hard


AUTHOR



STATUS

approved



