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A089726 Smallest prime of the form nk+1, k > n. 2

%I

%S 3,7,13,29,31,43,71,73,109,131,199,157,313,211,241,337,307,379,419,

%T 421,463,617,599,601,701,859,757,953,929,991,1117,1153,1123,1259,1471,

%U 1549,1481,1483,1873,1721,1723,1933,1979,2069,2161,2347,2351,2593,2549,2551

%N Smallest prime of the form nk+1, k > n.

%H Vincenzo Librandi, <a href="/A089726/b089726.txt">Table of n, a(n) for n = 1..1000</a>

%e a(7)=71 because 7*10+1=71 is prime, whereas 7*8+1=57 and 7*9+1=64 are composite.

%t f[n_] := Block[{k = n + 1}, While[ !PrimeQ[k*n + 1], k++ ]; k*n + 1]; Array[f, 50] (* _Robert G. Wilson v_, Dec 17 2009 *)

%Y Cf. A089727.

%K nonn,easy

%O 1,1

%A _Amarnath Murthy_, Nov 18 2003

%E More terms from _Hugo Pfoertner_, Apr 01 2004

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Last modified June 19 00:55 EDT 2019. Contains 324217 sequences. (Running on oeis4.)