OFFSET
0,1
MATHEMATICA
Flatten[Sort[Table[If[PrimeQ[Sum[FactorInteger[2^n - 1][[m]][[1]], {m, 1, Length[FactorInteger[2^n - 1]]}]], Sum[FactorInteger[2^n - 1][[m]][[1]], {m, 1, Length[FactorInteger[2^n - 1]]}], {}], {n, 0, 50}]]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Nov 22 2008
EXTENSIONS
Edited by N. J. A. Sloane, Nov 26 2008
STATUS
approved