A163184 Primes of the form 8k + 1 dividing 2^j + 1 for some odd j.

281, 617, 1033, 1049, 1097, 1193, 1481, 1553, 1753, 1777, 2281, 2393, 2473, 2657, 2833, 2857, 3049, 3529, 3673, 3833, 4049, 4153, 4217, 4273, 4457, 4937, 5113, 5297, 5881, 6121, 6449, 6481, 6521, 6529, 6569, 6761, 6793, 6841, 7121, 7129, 7481, 7577, 7817, 8081, 8233, 8537, 9001, 9137, 9209, 9241

Offset: 1

Author

Christopher J. Smyth, Jul 22 2009

Keywords

• easy
• nonn

Comments

Each term p has the form 2^r*j + 1, where r >= 3, j is odd, and ord_p(-2) divides j.

Examples

			281 is in the sequence as 281 = 2^3*35 + 1 and 281 | 2^35 + 1.
		

Crossrefs

Set difference of A163183 and A007520.

Subsequence of A033203, A051071, A051073, A051077, A051085, A051101.

Programs

Maple

with(numtheory):A:=NULL:p:=2: for c to 500 do p:=nextprime(p);if order(-2,p) mod 2=1 and p mod 8 = 1 then A:=A,p;;fi;od:A;

Extensions

More terms from Max Alekseyev, Sep 29 2016