OFFSET
1,1
COMMENTS
Previous name was: Smallest p primes which give q=2p+2n-1 primes. Smallest Sophie Germain primes generalized in a possible way: 1 is replaced by 2n-1.
FORMULA
Min{p|p and q=2p+2n-1 are primes}.
EXAMPLE
For n=1,2,3,4, 2n-1=1,3,5,7 and 2*{2,7,31,71,...} + {1,3,5,7,...} = {5,17,67,149,...}. For n=75, a(75)=140717 a prime gives 2*140717 + 75 = 281509, a new prime.
MATHEMATICA
Array[(k = 1; While[NextPrime[2 #2] - 2 #2 != #1 & @@ {#, Prime[k]}, k++]; Prime[k]) &[2 # - 1] &, 38] (* Michael De Vlieger, Oct 12 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Feb 26 2001
EXTENSIONS
Offset corrected by Sean A. Irvine, Oct 12 2022
New name from Sean A. Irvine, Oct 12 2022
STATUS
approved