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A073715
Prime preceding the n-th Mersenne prime.
4
2, 5, 29, 113, 8179, 131063, 524269, 2147483629, 2305843009213693921, 618970019642690137449562091, 162259276829213363391578010287957, 170141183460469231731687303715884105703
OFFSET
1,1
LINKS
FORMULA
a(n) = prime(primepi(A000668(n))-1).
From Amiram Eldar, Aug 10 2024: (Start)
a(n) = A151799(A000668(n)).
a(n) = A000668(n) - A365161(n). (End)
MAPLE
a:= n-> prevprime(numtheory[mersenne]([n])):
seq(a(n), n=1..12); # Alois P. Heinz, Oct 30 2024
MATHEMATICA
NextPrime[Select[2^Prime[Range[50]] - 1, PrimeQ], -1] (* Jayanta Basu, Jul 08 2013 *)
Table[NextPrime[2^MersennePrimeExponent[n] - 1, -1], {n, 1, 12}] (* Amiram Eldar, Aug 10 2024 *)
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Labos Elemer, Aug 05 2002
STATUS
approved