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A140745 Smallest prime p such that the Mersenne number A000225(p) = 2^p - 1 has exactly n prime factors (counted with multiplicity). 1
2, 11, 29, 157, 113, 223, 491, 431, 397 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 223, pp 63-4, Ellipse Paris 2008.

LINKS

Table of n, a(n) for n=1..9.

PROG

(PARI) a(n) = forprime(p=2, oo, if(bigomega(2^p-1)==n, return(p))); \\ Jinyuan Wang, Aug 10 2021

CROSSREFS

Cf. A000225, A001222, A046051, A136033.

Sequence in context: A220095 A133558 A285812 * A178629 A062802 A103830

Adjacent sequences:  A140742 A140743 A140744 * A140746 A140747 A140748

KEYWORD

nonn,more

AUTHOR

Lekraj Beedassy, Jul 12 2008

STATUS

approved

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Last modified May 17 10:16 EDT 2022. Contains 353745 sequences. (Running on oeis4.)