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A063788
Numbers k such that sigma(k) = 2k + Omega(k), where Omega(n) is the number of prime divisors of n (with repetition).
0
18, 88, 4030, 5830, 518656, 13174976, 134094848, 2146926592
OFFSET
1,1
COMMENTS
From Donovan Johnson_, Dec 19 2008: (Start)
a(9) <= 2251798907715584.
a(10) <= 633825300114085990300727115776.
a(11) <= 2596148429267411760623818083663872. (End)
a(9) > 10^13. - Giovanni Resta, Jul 13 2015
FORMULA
Numbers k such that A000203(k) = 2k + A001222(k). - Wesley Ivan Hurt, Oct 30 2022
PROG
(PARI) for(n=1, 10^8, if(sigma(n)==2*n+bigomega(n), print(n)))
CROSSREFS
Cf. A000203 (sigma), A001222 (Omega).
Sequence in context: A250101 A141842 A215191 * A066854 A247901 A369419
KEYWORD
more,nonn
AUTHOR
Jason Earls, Aug 16 2001
EXTENSIONS
a(7)-a(8) from Donovan Johnson, Dec 19 2008
STATUS
approved