A185372 Least positive integer which, when added to each of the first n Mersenne primes, yields all primes.

2, 4, 10, 10, 40, 40, 100, 32296, 65836, 214510186, 413879926, 1772668756

Offset

1,1

Comments

J. L. Selfridge proved that a(8) > 100.

Links

Table of n, a(n) for n=1..12.

Mathematica

lst = {}; p = 18; Do[p = Prime[n]; If[PrimeQ[2^p - 1], AppendTo[lst, p]], {n, p}]; Table[k = 1; While[i = 1; While[i <= n && PrimeQ[2^lst[[i]] + k], i++]; i <= n, k++]; k + 1, {n, Count[lst, _Integer]}]

Crossrefs

Cf. A000043.

Sequence in context: A092945 A320150 A056376 * A186757 A184876 A243622

Adjacent sequences: A185369 A185370 A185371 * A185373 A185374 A185375

Keyword

hard,more,nonn

Author

Arkadiusz Wesolowski, Jan 26 2012

Status

approved