

A183076


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


7



63, 1023, 16383, 32767, 67108863, 1073741823, 17179869183, 274877906943, 8796093022207, 2251799813685247, 4611686018427387903, 36893488147419103231
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OFFSET

1,1


COMMENTS

Needed factorizations are in the Cunningham Project.


LINKS

Table of n, a(n) for n=1..12.
S. S. Wagstaff, Jr., The Cunningham Project.


FORMULA

a(n) = 2^A183072(n)  1


EXAMPLE

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


CROSSREFS

Cf. A000668, A136005, A183075, A183077, A183078
Cf. A000043, A136003, A183071, A183072, A183073, A183074
Sequence in context: A112494 A258004 A258014 * A230660 A132465 A202983
Adjacent sequences: A183073 A183074 A183075 * A183077 A183078 A183079


KEYWORD

nonn,hard


AUTHOR

Stuart Clary, Dec 23, 2010


STATUS

approved



