OFFSET
2,1
COMMENTS
Also numbers n such that (2n + 1)/3 is prime. - Vicente Izquierdo Gomez, Dec 30 2012
FORMULA
a(n) = (3*prime(n)-1)/2.
EXAMPLE
3+2/2=4, 5+4/2=7, 7+6/2=10, 11+10/2=16,..
MATHEMATICA
f[n_]:=n/2; lst={}; Do[p=Prime[n]; AppendTo[lst, p+f[p-1]], {n, 2, 5!}]; lst
#+(#-1)/2&/@Prime[Range[2, 60]] (* Harvey P. Dale, Nov 04 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Nov 30 2009
EXTENSIONS
Edited by N. J. A. Sloane, Jan 04 2013
STATUS
approved