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

4102, 12295, 20487, 28680, 36871, 45064, 53256, 61449, 69639, 77832, 86024, 94217, 102408, 110601, 118793, 126986, 135175, 143368, 151560, 159753, 167944, 176137, 184329, 192522, 200712, 208905, 217097, 225290, 233481, 241674, 249866, 258059, 266247, 274440, 282632, 290825, 299016, 307209, 315401, 323594, 331784, 339977

Offset

1,1

Comments

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

Links

Donovan Johnson, Table of n, a(n) for n = 1..10000

Index entries for Colombian or self numbers and related sequences

Example

a(1) = 4102, the four k with A092391(k) = 4102 being:
4091 = '111111111011', A000120(4091) = 11, 4091 + 11 = 4102;
4092 = '111111111100', A000120(4092) = 12, 4092 + 10 = 4102;
4099 = '1000000000011', A000120(4099) = 3, 4099 + 3 = 4102;
4100 = '1000000000100', A000120(4100) = 2, 4100 + 2 = 4102.

Prog

(Haskell)
a227915 n = a227915_list !! (n-1)
a227915_list = filter ((== 4) . a228085) [1..]

Crossrefs

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

Sequence in context: A346337 A345634 A346347 * A371602 A168345 A255158

Adjacent sequences: A227912 A227913 A227914 * A227916 A227917 A227918

Keyword

nonn,base

Author

Reinhard Zumkeller, Oct 13 2013

Status

approved