OFFSET
1,3
COMMENTS
54% of a(n) for n=1 to 1755 are < 0.1*n^2.
LINKS
Pierre CAMI, Table of n, a(n) for n = 1..1755
MATHEMATICA
lon[n_]:=Module[{k=1, n2=3*2^n}, While[!PrimeQ[k*n2-1]||!PrimeQ[k*n2+1], k= k+2]; k]; Array[lon, 60] (* Harvey P. Dale, Nov 27 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Apr 07 2012
STATUS
approved