A124416 Numbers k such that 2*k+1, 4*k+1, 8*k+1, 16*k+1, 32*k+1, 64*k+1, 128*k+1 and 256*k+1 are primes.

7757430, 31286970, 360821505, 365536215, 414779430, 418803000, 428547690, 428823900, 434768475, 508654155, 584808795, 732681630, 809814510, 846079035, 857095380, 968314215, 1115279880, 1187901285, 1193371860, 1244805450

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..100

Mathematica

Select[15*Range[10^8], And @@ PrimeQ /@ ({2, 4, 8, 16, 32, 64, 128, 256}*# + 1) &] (* Ray Chandler, Nov 21 2006 *)
Select[15*Range[83*10^6], AllTrue[#*2^Range[8]+1, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 23 2020 *)

Crossrefs

Cf. A005097, A123998, A124041, A124412-A124417.

Sequence in context: A233597 A258954 A273101 * A320516 A319809 A347424

Adjacent sequences: A124413 A124414 A124415 * A124417 A124418 A124419

Keyword

nonn

Author

Artur Jasinski, Nov 02 2006

Extensions

Extended by Ray Chandler, Nov 21 2006

Status

approved