A139299 a(n) = 2^(2p - 1)/4-1, where p is the n-th Mersenne prime A000668(n).

7, 2047, 576460752303423487, 3618502788666131106986593281521497120414687020801267626233049500247285301247

Offset: 1

Author

Omar E. Pol, Apr 13 2008

Keywords

• nonn

Crossrefs

Cf. A000668, A139294, A139295, A139296, A139297, A139298, A139300, A139301, A139302, A139303, A139304, A139305, A139306.

Programs

Mathematica

a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 5) - 1; Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/4-1 = A139294(n)/4-1 = A139298(n)-1.

Extensions

a(4) from Amiram Eldar, Jul 10 2025