

A115186


Smallest number m such that m and m+1 have exactly n prime factors (counted with multiplicity).


15



2, 9, 27, 135, 944, 5264, 29888, 50624, 203391, 3290624, 6082047, 32535999, 326481920, 3274208000, 6929459199, 72523096064, 37694578688, 471672487935, 11557226700800, 54386217385983, 50624737509375, 275892612890624, 4870020829413375, 68091093855502335, 2280241934368767
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OFFSET

1,1


COMMENTS

Apparently, 4*a(n)+2 is the least number k such that k2 and k+2 have exactly n+2 prime factors, counted with multiplicity.  Hugo Pfoertner, Apr 02 2024


REFERENCES

J.M. De Koninck, Ces nombres qui nous fascinent, Entry 135, p. 46, Ellipses, Paris 2008.


LINKS



EXAMPLE

a(10) = 3290624 = 6427 * 2^9, 3290624+1 = 13 * 5^5 * 3^4:


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



