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A048880
Primes of form pq+2 where p and q are consecutive primes.
14
17, 37, 79, 223, 439, 4759, 22501, 32401, 53359, 57601, 60493, 72901, 77839, 95479, 99223, 159199, 164011, 176401, 194479, 239119, 324901, 378223, 416023, 497011, 680623, 756853, 804511, 1115113, 1664101, 1742401, 2223079
OFFSET
1,1
COMMENTS
All terms > 17 are congruent to 1 mod 6. - Zak Seidov, Dec 03 2010
FORMULA
a(n) = 6*A342564(n-1) + 1 for n >= 2. - Hugo Pfoertner, Jun 24 2021
EXAMPLE
487*491+2=239119.
MAPLE
with (numtheory): for n from 1 to 1000 do if (tau(ithprime(n)*ithprime(n+1)+2)=2) then print(ithprime(n), ithprime(n+1), ithprime(n)*ithprime(n+1)+2); fi; od;
MATHEMATICA
Reap[Do[If[PrimeQ[p=Prime[k]*Prime[k+1]+2], Sow[p]], {k, 1, 430}]][[2, 1]] (* Zak Seidov Dec 03 2010 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Herman H. Rosenfeld (herm3(AT)pacbell.net)
EXTENSIONS
Corrected and extended by Joe DeMaio (jdemaio(AT)kennesaw.edu).
STATUS
approved