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%I #11 Mar 31 2012 10:26:44
%S 2,2,3,5,5,154769,2894219,2894219,407874179,214580145779,
%T 9448481062019,247236503934419,2545206711847799,18178612369988250179,
%U 53792264108455702829
%N a(n) = least k such that all of k, 2k+1, 3k+2, ..., nk+n-1 are primes, or 0 if no such k is found.
%C a(10) > 3691000000, _Robert G. Wilson v_, Mar 23 2007
%C By definition the same as A088651(n)-1 if k exists. It is conjectured k always exists. - a(10)-a(15) from _Jens Kruse Andersen_, May 02 2008
%t f[1] = 2; f[n_] := f[n] = Block[{k = PrimePi@ f[n - 1], p, t = Table[i*p + (i - 1), {i, 2, n}]}, While[p = Prime@k; Union@PrimeQ@t != {True}, k++ ]; p]; Do[ Print[f@n // Timing], {n, 10}] (* _Robert G. Wilson v_, Mar 23 2007 *)
%Y Cf. A000040, A005384, A067256, A067257, A067258, A101767, A101768, A101769, A101770.
%Y Cf. A088651.
%K nonn
%O 1,1
%A _Jonathan Vos Post_ and _Ray Chandler_, Jan 13 2005
%E a(10)-a(15) from _Jens Kruse Andersen_, May 02 2008