A176680 Primes p == 2 (mod 3) of the form 2^n-3.

5, 29, 509, 536870909, 13164036458569648337239753460458804039861886925068638906788872189, 3369993333393829974333376885877453834204643052817571560137951281149, 13803492693581127574869511724554050904902217944340773110325048447598589

Offset

1,1

Comments

Also primes of the form 2^(2k+1)-3, since 2^n-3 == 2 (mod 3) iff n is odd. - Robert Israel, Feb 17 2016

Links

Robert Israel, Table of n, a(n) for n = 1..11

Maple

map(t -> 2^t-3, select(t -> isprime(2^t-3), [seq(t, t=1..2000, 2)])); # Robert Israel, Feb 17 2016

Mathematica

Flatten[Table[If[IntegerQ[Rationalize[N[ (1 + 2^n)/ 3]]] && PrimeQ[2^n - 3], 2^n - 3, {}], {n, 2, 100000}]]

Prog

(Magma) [2^n-3: n in [1..300] | IsPrime(2^n-3) and (2^n-3) mod 3 eq 2] - Jaroslav Krizek, Feb 17 2016

Crossrefs

Cf. A050414.

Sequence in context: A202758 A197962 A259534 * A352948 A352951 A069142

Adjacent sequences: A176677 A176678 A176679 * A176681 A176682 A176683

Keyword

nonn

Author

Roger L. Bagula, Apr 23 2010

Extensions

Definition corrected by Jaroslav Krizek, Feb 17 2016

a(5)-a(7) from Jaroslav Krizek, Feb 17 2016

Status

approved