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

Author

Reinhard Zumkeller, Oct 13 2013

Keywords

• nonn
• base

Comments

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

Examples

			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.
		

Links

• Donovan Johnson, Table of n, a(n) for n = 1..10000
• Index entries for Colombian or self numbers and related sequences

Crossrefs

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

Programs

Haskell

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