A091180 Primes of the form 3*p - 2 such that p is a prime.
7, 13, 19, 31, 37, 67, 109, 127, 139, 157, 181, 199, 211, 307, 337, 379, 409, 487, 499, 541, 571, 577, 631, 751, 769, 787, 811, 829, 877, 919, 937, 991, 1009, 1039, 1117, 1201, 1291, 1297, 1327, 1381, 1399, 1459, 1471, 1567, 1621, 1669, 1759, 1777, 1801
Offset: 1
Examples
From _K. D. Bajpai_, Jun 20 2015: (Start) a(4) = 31: 3*11 - 2 = 31; A088878(4) = 11. a(6) = 67: 3*23 - 2 = 67; A088878(6) = 23. (End)
Links
- K. D. Bajpai, Table of n, a(n) for n = 1..10000
Programs
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Magma
[ k: p in PrimesUpTo(1000) | IsPrime(k) where k is (3*p-2) ]; // K. D. Bajpai, Jun 20 2015
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Maple
A091180:= n-> (3*ithprime(n)-2): select(isprime,[seq((A091180(n), n=1..100))]); # K. D. Bajpai, Jun 20 2015
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Mathematica
n = 1; a = {}; Do[If[PrimeQ[(Prime[k] + 2n)/(2n + 1)], AppendTo[a, Prime[k]]], {k, 1, 500}]; a (* Artur Jasinski, Dec 12 2007 *) Select[Table[3*Prime[n] - 2,{n, 1000}], PrimeQ] (* K. D. Bajpai, Jun 20 2015 *) -
PARI
forprime(p = 1, 1000, k =( 3*p -2); if ( isprime(k), print1(k, ", "))); \\ K. D. Bajpai, Jun 20 2015
Formula
a(n) = 3*A088878(n)-2.
Extensions
Name clarified by Jinyuan Wang, Aug 06 2021
Comments