|
| |
|
|
A074973
|
|
Smallest index i such that NextPrime[p2 := 2*Prime[i]] - p2 = 2n - 1.
|
|
0
| |
|
|
1, 4, 11, 20, 17, 67, 104, 56, 125, 165, 182, 316, 236, 359, 407, 1254, 667, 836, 1521, 1210, 1966, 3197, 1520, 2294, 2279, 2046, 5410, 5472, 1965, 6702, 13947, 10138, 12122, 16760, 7659, 22325, 16784, 13072, 36169, 17852, 15414, 69872, 23814
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| First index i such that NextPrime[p2=2*Prime[i]]-p2 is 2n-1; case n=1 corresponds to Sophie Germain (SG) primes, others may be called SG n-primes. Distance between 2*(n-th prime) and next prime in A059787.
|
|
|
EXAMPLE
| a(54) = 342337 because difference between 2*p(342337) and next prime is 2*54 -1 = 107 and 342337 is the smallest such index.
|
|
|
CROSSREFS
| Cf. A059787.
Sequence in context: A038431 A009908 A049935 * A025526 A047962 A047961
Adjacent sequences: A074970 A074971 A074972 * A074974 A074975 A074976
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Oct 06 2002
|
| |
|
|
