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%I #7 May 18 2013 16:49:19
%S 1,1,1,2,1,1,3,1,2,2,1,1,2,3,1,2,1,1,2,1,1,3,4,2,2,1,1,2,3,2,5,1,1,2,
%T 1,3,3,1,2,3,1,1,5,7,1,2,3,1,3,1,5,5,1,2,2,1,1,2,13,1,2,3,1,5,4,1,6,1,
%U 3,3,1,3,5,3,2,2,1,1,2,4,2,3,1,7,3,3,1,5,4,1,2,1,2,2,1,1,3,4,3,5,6,3,2,4
%N Least k such that 4*n*k-1 is a prime.
%H Harvey P. Dale, <a href="/A037034/b037034.txt">Table of n, a(n) for n = 1..1000</a>
%e a(5)=1 because 4*5*1-1=19 is a prime
%t lk[n_]:=Module[{c=4n,k=1},While[!PrimeQ[c*k-1],k++];k]; Array[lk,110] (* _Harvey P. Dale_, Jun 05 2012 *)
%Y Cf. A016014.
%K nonn
%O 1,4
%A _Felice Russo_
%E More terms from _Erich Friedman_
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