OFFSET
1,1
COMMENTS
Except for having an additional first term the sequence coincides with A084704.
For n>2, a(n)-prime(n) is a multiple of 12, e.g., 17-5, 19-7, 23-11, etc. - Zak Seidov, Oct 15 2015
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
EXAMPLE
2+7=9=3*3 (semiprime), 3+7=10=2*5 (semiprime), 5+17=22=2*11 (semiprime).
MATHEMATICA
sp[n_]:=Module[{np=NextPrime[n]}, While[PrimeOmega[n+np]!=2, np= NextPrime[ np]]; np]; sp/@Prime[Range[60]] (* Harvey P. Dale, Apr 06 2016 *)
PROG
(PARI) a(n) = {q = prime(n); p = nextprime(q+1); while (bigomega(p+q)!=2, p = nextprime(p+1)); p; } \\ Michel Marcus, Oct 15 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Sep 04 2009
EXTENSIONS
Prior Mathematica program deleted by Harvey P. Dale, Apr 06 2016
STATUS
approved