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A111947 Admirable Harshad numbers. 3

%I #9 Oct 27 2019 11:12:03

%S 12,20,24,30,40,42,54,70,84,102,114,120,140,222,224,234,270,308,364,

%T 402,476,644,1002,1148,1204,1638,1652,2022,2202,2212,3164,3250,3472,

%U 4172,6200,7588,8204,8432,8596,9424,10002,10014,10724,10792,11202,11228

%N Admirable Harshad numbers.

%H Amiram Eldar, <a href="/A111947/b111947.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3)=24 because 1+2+3+4+8+12-6 = 24 and 24/6 = 4.

%t harsQ[n_] := Divisible[n, Plus @@ IntegerDigits[n]]; admQ[n_] := (ab = DivisorSigma[1, n] - 2 n) > 0 && EvenQ[ab] && ab/2 < n && Divisible[n, ab/2]; Select[Range[12000], harsQ[#] && admQ[#] &] (* _Amiram Eldar_, Oct 27 2019 *)

%Y Intersection of A005349 and A111592.

%Y Cf. A111948.

%K base,nonn

%O 1,1

%A _Jason Earls_, Aug 22 2005

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Last modified April 19 19:02 EDT 2024. Contains 371798 sequences. (Running on oeis4.)