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 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 (list; graph; refs; listen; history; text; internal format)
 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 M. F. Hasler, Table of n, a(n) for n = 1..200, Sep 11 2019 FORMULA Equals A033880 o A153501. 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 Cf. A033880, A153501, A181595. Sequence in context: A033882 A062111 A181596 * A033881 A099406 A274601 Adjacent sequences: A182139 A182140 A182141 * A182143 A182144 A182145 KEYWORD nonn AUTHOR M. F. Hasler, Apr 14 2012 STATUS approved

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Last modified July 12 19:36 EDT 2024. Contains 374252 sequences. (Running on oeis4.)