A139297 a(n) = 2^(2p - 1)/2-1, where p is the n-th Mersenne prime A000668(n).

15, 4095, 1152921504606846975, 7237005577332262213973186563042994240829374041602535252466099000494570602495

Offset: 1

Author

Omar E. Pol, Apr 13 2008

Keywords

• nonn

Crossrefs

Cf. A000668, A139294, A139295, A139296, A139298, A139299, A139300, A139301, A139302, A139303, A139304, A139305, A139306.

Programs

Mathematica

a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 4) - 1; Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/2-1 = A139296(n)-1.

Extensions

a(4) from Amiram Eldar, Jul 10 2025