A140745 - OEIS

A140745

Smallest prime p such that the Mersenne number A000225(p) = 2^p - 1 has exactly n prime factors (counted with multiplicity).

2, 11, 29, 157, 113, 223, 491, 431, 397

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OFFSET

1,1

REFERENCES

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

LINKS

PROG

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

CROSSREFS

KEYWORD

nonn,more

AUTHOR

STATUS

approved