OFFSET
1,1
COMMENTS
Primes of the form 2*prime(n) + prime(2*n): 7, 13, 23, 107, 163, 193, 257, 401, 457, 547, 647, 661, 709, 857, 877, 1201,...
EXAMPLE
a(1)=7 because 7 is prime and 2*prime(1) + prime(2*1) = 4 + 3 = 7.
a(2) = 13 because 13 is prime and 2*prime(2) + prime(2*2) = 6 + 7 = 13.
MATHEMATICA
Table[k = 1; While[p = k*Prime[n] + Prime[k*n]; ! PrimeQ[p], k++]; p, {n, 100}] (* T. D. Noe, Sep 03 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Irina Gerasimova, Aug 31 2013, Sep 04 2013
EXTENSIONS
Corrected by R. J. Mathar, Sep 02 2013
STATUS
approved