OFFSET
1,2
MATHEMATICA
BTSeg[d_Integer] := Module[{}, {3^d - (3^d - 1)/2, 3^d + (3^d - 1)/2}];
Table[s = BTSeg[d]; PrimePi[Ceiling[s[[2]]/2]*2] - PrimePi[s[[1]] - 1], {d, 0, 29}]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Lei Zhou, Dec 17 2013
STATUS
approved