A187088 Least odd k such that k*2^(2^n)+1 is prime.

1, 1, 1, 1, 1, 43, 25, 21, 207, 223, 1125, 2577, 3091, 9165, 6223, 3493, 1063

Offset

0,6

Links

Table of n, a(n) for n=0..16.

Mark Rodenkirch: OpenPFGW (for running the PFGW the program).

Mathematica

Table[k=1; While[! PrimeQ[k*2^2^n + 1], k=k+2]; k, {n, 0, 10}]

Prog

(PFGW)
SCRIPT
DIM nn, -1
DIM kk
DIMS tt
LABEL loopn
SET nn, nn+1
SET kk, -1
LABEL loopk
SET kk, kk+2
SETS tt, %d, %d\,; nn; kk
PRP kk*2^(2^nn)+1, tt
IF ISPRP THEN GOTO loopn
GOTO loopk
\PFGW -t FILE.txt
FILE.txt =
ABC $a
43*2^(2^5)+1
25*2^(2^6)+1
21*2^(2^7)+1
207*2^(2^8)+1
223*2^(2^9)+1
1125*2^(2^10)+1
2577*2^(2^11)+1
3091*2^(2^12)+1
9165*2^(2^13)+1
6223*2^(2^14)+1
3493*2^(2^15)+1
1063*2^(2^16)+1

Crossrefs

Sequence in context: A097398 A225210 A033363 * A127147 A298078 A291494

Adjacent sequences: A187085 A187086 A187087 * A187089 A187090 A187091

Keyword

nonn

Author

Pierre CAMI, Mar 08 2011

Status

approved