A224789 Primes p such that both p + nextprime(p) + 1 and p*nextprime(p) + 2 are primes.
5, 7, 13, 19, 67, 229, 269, 307, 313, 401, 439, 613, 643, 863, 1051, 1693, 1783, 1999, 2143, 2239, 2309, 2423, 2549, 2753, 2819, 3037, 3079, 3089, 3361, 3373, 3389, 3677, 3863, 3877, 4139, 4259, 4519, 4663, 4909, 4933, 5323, 5527, 5581, 5849, 6359, 6577
Offset: 1
Keywords
Examples
5 is a member since 5 + 7 + 1 = 13 and 5 * 7 + 2 = 37 are both primes.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
Select[Prime[Range[900]], PrimeQ[# + NextPrime[#] + 1] && PrimeQ[#*NextPrime[#] + 2] &] npQ[n_]:=Module[{np=NextPrime[n]},AllTrue[{n+np+1,n*np+2},PrimeQ]]; Select[ Prime[ Range[900]],npQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 04 2017 *)
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