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

7, 2047, 576460752303423487, 3618502788666131106986593281521497120414687020801267626233049500247285301247

Offset

1,1

Links

Table of n, a(n) for n=1..4.

Formula

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

Mathematica

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

Crossrefs

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

Sequence in context: A248730 A024099 A056235 * A004818 A125538 A373035

Adjacent sequences: A139296 A139297 A139298 * A139300 A139301 A139302

Keyword

nonn

Author

Omar E. Pol, Apr 13 2008

Extensions

a(4) from Amiram Eldar, Jul 10 2025

Status

approved