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Record values in A194606.
12

%I #20 Apr 03 2023 10:36:12

%S 0,1,2,4,5,6,11,17,20,28,70,99,150,726,7431,22394,85461,191207

%N Record values in A194606.

%C The index sequence of this one is 1, 3, 6, 15, 17, 29, 53, 115, 186, 220, 229, 1886, 5344, 5736, 66774, 1087403, 14747671, 158018119.

%C a(17) was found in 2000 by Wilfrid Keller and a(18) was found in 2003 by _Patrick De Geest_.

%D Wilfrid Keller, personal communication, 2010.

%H Chris K. Caldwell, The List of Largest Known Primes, <a href="https://t5k.org/primes/page.php?id=6614">270704167 * 2^85461 - 1</a>

%H Chris K. Caldwell, The List of Largest Known Primes, <a href="https://t5k.org/primes/page.php?id=596">3296757029 * 2^191207 + 1</a>

%H Carlos Rivera, <a href="http://www.primepuzzles.net/problems/prob_030.htm">Problem 30</a>

%e A194606(53) = 11 since A194606(115) = 17 is the next record value.

%t l = -1; Flatten[Table[p = Prime[n]; k = 0; While[! PrimeQ[p*2^k - 1] && ! PrimeQ[p*2^k + 1], k++]; If[k > l, l = k, {}], {n, 10^4}]] (* _Arkadiusz Wesolowski_, Sep 04 2011 *)

%Y Cf. A194591, A194600, A194603, A194606, A194608, A194635, A194636, A194637, A194638, A194639.

%Y Cf. A103963, A103964, A076335, A180247.

%K more,nonn

%O 1,3

%A _Arkadiusz Wesolowski_, Aug 30 2011