

A182142


Abundance d = sigma(N)  2*N = A033880(N) of numbers N = A153501(n), i.e., N has d > 0 as divisor.


1



4, 3, 2, 12, 10, 8, 4, 2, 120, 7, 56, 78, 8, 2, 2, 672, 32, 16, 4, 2, 532, 152, 136, 8, 68, 31, 992, 128, 8, 64, 32, 16, 4, 8, 128, 32, 8, 2, 43648, 2528, 32, 4, 2, 523776, 32, 2272, 32, 32, 127, 16256, 32, 32, 4, 536, 8, 32, 8, 52, 16, 32, 41044, 64
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OFFSET

1,1


COMMENTS

It is conjectured that only powers of 2 can occur more than once.
Thanks to Amiram Eldar, reference to A181595 in the definition has been corrected to A153501 (which does include triperfect numbers, as required here, in contrast to A181595 where these are excluded).  M. F. Hasler, Sep 11 2019


LINKS



FORMULA



PROG

(PARI) f182142(n)={my(d=sigma(n)2*n); d>0 && !(n%d) && return(d)} /* Note: This is A033880(n)*is_A153501(n), neither A182142 nor is_A182142. */
for(n=1, 1e6, (t=f182142(n))&&print1(t", "))


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



