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A139296
a(n) = 2^(2p - 1)/2, where p is the n-th Mersenne prime A000668(n).
11
16, 4096, 1152921504606846976, 7237005577332262213973186563042994240829374041602535252466099000494570602496
OFFSET
1,1
COMMENTS
a(5) has 4931 digits and is too large to include. - R. J. Mathar, May 30 2008
FORMULA
a(n) = 2^(2*A000668(n)-1)/2.
MATHEMATICA
a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 4); Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)
KEYWORD
nonn
AUTHOR
Omar E. Pol, Apr 13 2008
EXTENSIONS
One more term from R. J. Mathar, May 30 2008
STATUS
approved