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A033859 Numbers k such that A033831(k) = A034444(k) where A034444(k) = number of unitary divisors of k. 1
8, 16, 24, 27, 36, 40, 54, 81, 88, 100, 104, 120, 125, 135, 136, 152, 168, 184, 189, 196, 225, 232, 248, 250, 264, 270, 272, 280, 296, 297, 312, 328, 343, 344, 351, 375, 376, 378, 408, 424, 440, 441, 456, 459, 472, 484, 488, 513, 520, 536, 568, 584, 594, 616 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MAPLE

with(numtheory): for n from 1 to 1200 do it := divisors(n): count := 0: for i from 1 to nops(it) do if it[i]>=3 and 1<=n/it[i] and n/it[i]<=(it[i]-2) then count := count+1 fi:od: if count=2^nops(ifactors(n)[2]) then printf(`%d, `, n) fi; od:

MATHEMATICA

j[n_] := DivisorSum[n, 1&, # > 2 && n/# < #-1 &]; Select[Range[1000], j[#] == 2^PrimeNu[#] &] (* Amiram Eldar, Jun 11 2019 *)

CROSSREFS

Cf. A033831, A034444.

Sequence in context: A228957 A137845 A046099 * A177899 A246311 A244371

Adjacent sequences:  A033856 A033857 A033858 * A033860 A033861 A033862

KEYWORD

easy,nonn

AUTHOR

Naohiro Nomoto

EXTENSIONS

More terms from James A. Sellers, Jun 20 2000

STATUS

approved

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Last modified November 13 17:34 EST 2019. Contains 329106 sequences. (Running on oeis4.)