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A277634 a(n) = 2^A000668(n) - 1. 0
7, 127, 2147483647, 170141183460469231731687303715884105727 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The terms of this sequence are sometimes called "Double Mersenne numbers" (cf. A263686).
Agrees with A077586 in the first four terms, but then the two sequences differ for the first time at n = 5, because prime(5) = 11 is not in A000043.
a(5) is too large to include in data section (see A276641).
a(n) = A263686(n) iff a(n) is prime, which is the case iff A000668(n) is in A103901.
Agrees with A263686 at least in the first four terms. - Omar E. Pol, Oct 24 2016
LINKS
FORMULA
a(n) = A000225(A000668(n)).
PROG
(PARI) forprime(p=1, 11, if(ispseudoprime(2^p-1), print1(2^(2^p-1)-1, ", ")))
CROSSREFS
Sequence in context: A134722 A053713 A077586 * A309130 A263686 A002614
KEYWORD
nonn,bref
AUTHOR
Felix Fröhlich, Oct 24 2016
STATUS
approved

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Last modified March 28 16:12 EDT 2024. Contains 371254 sequences. (Running on oeis4.)