%I #43 Sep 21 2024 12:41:12
%S 3,3,2,3,19,5,13,7,17,19,43,11,103,13,29,31,67,17,37,19,41,43,367,23,
%T 199,103,53,223,463,29,61,31,131,67,139,71,73,37,311,79,163,41,5503,
%U 43,89,367,751,47,97,199,101,103,211,53,109,223,113,463,241663,59,487,61
%N Riesel problem: Smallest prime of form n*2^m-1, m >= 0, or 0 if no such prime exists.
%H Reinhard Zumkeller, <a href="/A038699/b038699.txt">Table of n, a(n) for n = 1..650</a>
%H Hans Riesel, <a href="/A076337/a076337.pdf">Some large prime numbers</a>. Translated from the Swedish original (Några stora primtal, Elementa 39 (1956), pp. 258-260) by Lars Blomberg.
%t getm[n_]:=Module[{m=0},While[!PrimeQ[n 2^m-1],m++];n 2^m-1]; Array[getm,80] (* _Harvey P. Dale_, Apr 24 2011 *)
%o (Haskell)
%o a038699 = until ((== 1) . a010051) ((+ 1) . (* 2)) . (subtract 1)
%o -- _Reinhard Zumkeller_, Mar 05 2012
%Y Primes arising in A040081 (or 0 if no prime exists).
%Y Main sequences for Riesel problem: A038699, A040081, A046069, A050412, A052333, A076337, A101036, A108129.
%Y Cf. A050921, A010051, A000079.
%K nonn,nice,changed
%O 1,1
%A _N. J. A. Sloane_, Dec 30 1999
%E More terms from _Henry Bottomley_, Apr 24 2001