A194607 Record values in A194606.

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

Offset: 1

Author

Arkadiusz Wesolowski, Aug 30 2011

Keywords

• more
• nonn

Comments

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.

a(17) was found in 2000 by Wilfrid Keller and a(18) was found in 2003 by Patrick De Geest.

Examples

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

References

• Wilfrid Keller, personal communication, 2010.

Links

• Chris K. Caldwell, The List of Largest Known Primes, 270704167 * 2^85461 - 1
• Chris K. Caldwell, The List of Largest Known Primes, 3296757029 * 2^191207 + 1
• Carlos Rivera, Problem 30

Crossrefs

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

Cf. A103963, A103964, A076335, A180247.

Programs

Mathematica

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 *)