A137877 Numbers k such that 18*k - 1 and 18*k + 1 are twin primes.
1, 4, 6, 10, 11, 15, 24, 29, 45, 46, 49, 59, 64, 71, 90, 104, 111, 116, 119, 126, 130, 144, 155, 165, 176, 181, 185, 196, 199, 204, 214, 225, 231, 235, 241, 249, 251, 266, 274, 276, 279, 301, 314, 319, 325, 326, 350, 364, 365, 370, 386, 396, 406, 416, 420, 431
Offset: 1
Keywords
Examples
1 is in the sequence since 18*1 - 1 = 17 and 18*1 + 1 = 19 are twin primes.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
q=18; lst={}; Do[r=n*q; If[PrimeQ[r-1]&&PrimeQ[r+1], AppendTo[lst, n]], {n, 1, 10^3}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 07 2008 *)