A134721 Bisection of Mersenne primes A000668.
3, 31, 8191, 524287, 2305843009213693951, 162259276829213363391578010288127
Offset: 1
Examples
a(3) = 8191 because the (2*3-1=5)th Mersenne prime is 8191.
Formula
a(n) = A000668(2*n - 1).
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