1,1
Table of n, a(n) for n=1..9.
s=1; Reap[Do[s=s+2^Prime[n]; If[PrimeQ[s], Sow[Prime[n]]], {n, 2000}]][[2, 1]]
Sequence in context: A180422 A055502 A003173 * A160434 A139630 A245738
Adjacent sequences: A159259 A159260 A159261 * A159263 A159264 A159265
nonn
T. D. Noe, Apr 07 2009
approved