A098929 Smallest k>0 such that (2^k)*A002110(n) + 1 is prime.

1, 1, 1, 1, 1, 2, 3, 11, 2, 4, 1, 2, 3, 15, 23, 6, 11, 1, 7, 6, 7, 10, 1, 9, 28, 1, 3, 7, 63, 1, 25, 29, 13, 3, 25, 12, 9, 18, 20, 15, 66, 3, 5, 39, 10, 37, 15, 14, 31, 6, 9, 27, 12, 7, 15, 12, 6, 11, 41, 35, 116, 15, 7, 28, 6, 9, 23, 28, 23, 2, 2, 9, 5, 17, 27, 56, 69, 132, 29, 1, 20, 17

Offset

1,6

Links

Pierre CAMI, Table of n, a(n) for n = 1..1029

Mathematica

f[n_] := Block[{k = 1, p = Product[Prime[i], {i, n}]}, While[ !PrimeQ[2^k*p + 1], k++ ]; k]; Table[ f[n], {n, 82}]

Prog

(PFGW & SCRIPT)
Command pfgw64 -f in.txt
in.txt = SCRIPT file
SCRIPT
DIM n, 0
DIM i, 0
DIM pp
DIMS t
OPENFILEOUT myf, a(n).txt
LABEL loop1
SET n, n+1
SET i, 0
LABEL loop2
SET i, i+1
SETS t, %d, %d, %d\,; n; p(n); i
SET pp, (2^i)*p(n)#+1
PRP pp, t
IF ISPRP THEN GOTO a
GOTO loop2
LABEL a
WRITE myf, t
GOTO loop1

Crossrefs

Cf. A002110, A097099.

Sequence in context: A002443 A111788 A238455 * A073098 A201267 A046641

Adjacent sequences: A098926 A098927 A098928 * A098930 A098931 A098932

Keyword

nonn

Author

Pierre CAMI and Robert G. Wilson v, Sep 27 2004

Status

approved