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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The Mersenne primes (A000668) are contained in this sequence.

Needed factorizations are in the Cunningham Project.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..54

S. S. Wagstaff, Jr., The Cunningham Project.

FORMULA

a(n) = 2^A183071(n) - 1.

EXAMPLE

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

CROSSREFS

Cf. A000668, A136005, A183076, A183077, A183078.

Cf. A000043, A136003, A183071, A183072, A183073, A183074.

Sequence in context: A145479 A077315 A080168 * A292890 A042131 A109140

Adjacent sequences:  A183072 A183073 A183074 * A183076 A183077 A183078

KEYWORD

nonn,hard

AUTHOR

Stuart Clary, Dec 23 2010

STATUS

approved

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Last modified March 21 22:19 EDT 2019. Contains 321382 sequences. (Running on oeis4.)