|
Search: id:A098142
|
|
|
| A098142 |
|
Numbers n such that (p*(q-1)+(p-1)*q)/2 is prime, where p and q are consecutive odd primes, p<q and p_n is the n-th prime. |
|
+0
2
|
|
| 2, 3, 5, 9, 13, 15, 17, 26, 35, 43, 56, 60, 80, 81, 83, 86, 89, 101, 102, 104, 120, 140, 152, 157, 170, 178, 191, 201, 204, 215, 219, 223, 238, 252, 286, 293, 296, 324, 329, 350, 359, 373, 383, 392, 395, 398, 412, 416, 424, 444, 458, 468, 479, 487, 497, 503, 514
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
MATHEMATICA
|
f[n_] := Block[{p = Prime[n], q = Prime[n + 1]}, r = (p*(q - 1) + (p - 1)*q)/2; If[ PrimeQ[r], r, 0]]; Select[ Range[522], f[ # ] != 0 &]
|
|
CROSSREFS
|
The generator of A099911.
Sequence in context: A108168 A087146 A033945 this_sequence A066821 A108568 A064386
Adjacent sequences: A098139 A098140 A098141 this_sequence A098143 A098144 A098145
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com) and Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 02 2004
|
|
|
Search completed in 0.002 seconds
|
