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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A138918 Numbers n such that 18n-1 is prime.

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%I A138918 #29 Sep 08 2022 08:45:33
%S A138918 1,3,4,5,6,10,11,13,14,15,20,24,25,26,28,29,31,33,36,38,39,40,43,45,
%T A138918 46,48,49,53,54,59,61,64,66,68,70,71,76,80,83,84,88,89,90,91,95,104,
%U A138918 105,106,110,111,115,116,119,123,126,130,131,133,134,136,144,145,148,150
%N A138918 Numbers n such that 18n-1 is prime.
%C A138918 Corresponding primes are in A061242.
%C A138918 No terms in this sequence end with 2 or 7 (18n-1 ends with 5 when the last digit of n is 2 or 7). - _David Garber_, Jun 25 2015
%H A138918 Zak Seidov, <a href="/A138918/b138918.txt">Table of n, a(n) for n = 1..1000</a>
%t A138918 Select[Range[200],PrimeQ[18#-1]&]  (* _Harvey P. Dale_, Mar 09 2011 *)
%o A138918 (Python)
%o A138918 from gmpy2 import divexact, t_mod
%o A138918 from sympy import prime
%o A138918 A138918 = [divexact(p+1,18) for p in (prime(n) for n in range(1,10**6)) if not t_mod(p+1,18)] # _Chai Wah Wu_, Sep 02 2014
%o A138918 (PARI) for(n=1,10^3,if(isprime(18*n-1),print1(n,", "))) \\ _Derek Orr_, Sep 03 2014
%o A138918 (Magma) [n: n in [0..150] | IsPrime(18*n-1)]; // _Vincenzo Librandi_, Jun 27 2015
%Y A138918 Cf. A061242, A258663.
%K A138918 nonn,easy
%O A138918 1,2
%A A138918 _Zak Seidov_, Apr 03 2008