OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = (A165811(n)-1)/18.
EXAMPLE
For p=2, 18*p+1=37. For p=7, 18*p+1=127. For p=11, 18*p+1=199.
MATHEMATICA
Select[Prime[Range[1000]], PrimeQ[18#+1]&] (* Harvey P. Dale, Mar 06 2011 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Sep 28 2009
EXTENSIONS
Extended by R. J. Mathar, Oct 16 2009
STATUS
approved