OFFSET
1,1
COMMENTS
a(1) and a(2) are themselves Sophie Germain primes.
LINKS
Nathaniel Johnston, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
a(1) = 2 = first Sophie Germain prime A005384(1). a(2) = 5 = sum of first two Sophie Germain primes = 2+3. a(3) = 73 = sum of first six Sophie Germain primes = 2+3+5+11+23+29.
MATHEMATICA
Select[Accumulate[Select[Prime[Range[5000]], PrimeQ[2#+1]&]], PrimeQ] (* Harvey P. Dale, Nov 27 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Jan 23 2010
EXTENSIONS
a(7) - a(34) from Nathaniel Johnston, Apr 29 2011
STATUS
approved