OFFSET
1,1
COMMENTS
3+(5^2-3^2)=3+16=19,..
Let x be the lesser of twin prime pairs. The sequence contains terms such that 5*x+4 is prime. - Harvey P. Dale, Sep 11 2012
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
lst={}; Do[p1=Prime[n]; p2=p1+2; If[PrimeQ[p2] && PrimeQ[p1+(p2^2-p1^2)], AppendTo[lst, p1]], {n, 1000}]; lst
With[{ltp=Transpose[Select[Partition[Prime[Range[600]], 2, 1], #[[2]]- #[[1]]==2&]][[1]]}, Select[ltp, PrimeQ[5#+4]&]] (* Harvey P. Dale, Sep 11 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Apr 02 2010
STATUS
approved