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A227915 Numbers of the form k + wt(k) for exactly four distinct k, where wt(k) = A000120(k) is the binary weight of k. 11

%I

%S 4102,12295,20487,28680,36871,45064,53256,61449,69639,77832,86024,

%T 94217,102408,110601,118793,126986,135175,143368,151560,159753,167944,

%U 176137,184329,192522,200712,208905,217097,225290,233481,241674,249866,258059,266247,274440,282632,290825,299016,307209,315401,323594,331784,339977

%N Numbers of the form k + wt(k) for exactly four distinct k, where wt(k) = A000120(k) is the binary weight of k.

%C Numbers occurring exactly four times in A092391: A228085(a(n)) = 4. For the first number that appears k times, see A230303.

%H Donovan Johnson, <a href="/A227915/b227915.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a>

%e a(1) = 4102, the four k with A092391(k) = 4102 being:

%e 4091 = '111111111011', A000120(4091) = 11, 4091 + 11 = 4102;

%e 4092 = '111111111100', A000120(4092) = 12, 4092 + 10 = 4102;

%e 4099 = '1000000000011', A000120(4099) = 3, 4099 + 3 = 4102;

%e 4100 = '1000000000100', A000120(4100) = 2, 4100 + 2 = 4102.

%o (Haskell)

%o a227915 n = a227915_list !! (n-1)

%o a227915_list = filter ((== 4) . a228085) [1..]

%Y Cf. A092391, A228085, A230092, A230091, A228088, A010061, A230093, A230303.

%K nonn,base

%O 1,1

%A _Reinhard Zumkeller_, Oct 13 2013

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Last modified October 21 08:47 EDT 2019. Contains 328292 sequences. (Running on oeis4.)