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A050586
Numbers n such that 121*2^n-1 is a prime.
1
1, 3, 21, 27, 37, 43, 91, 117, 141, 163, 373, 421, 1581, 2035, 10701, 18931, 21307, 51195, 64579, 156541, 302097, 334257, 368059, 383061, 410131, 494317, 541621, 990219, 1039965, 1526097, 1589157, 1695499, 1954243, 2033941
OFFSET
1,2
COMMENTS
4553899 is also in the sequence. - Felix Fröhlich, Jul 04 2014
MATHEMATICA
Select[Range[2500], PrimeQ[121*2^# - 1] &] (* Michael De Vlieger, Dec 10 2020 *)
CROSSREFS
Cf. A032410.
Sequence in context: A067233 A007648 A273481 * A074217 A350247 A062219
KEYWORD
hard,nonn
AUTHOR
N. J. A. Sloane, Dec 29 1999
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
STATUS
approved