A230300 - OEIS

%I #14 Jul 05 2024 14:06:40

%S 1,3,4,6,6,8,9,11,10,12,13,15,15,17,18,20,18,20,21,23,23,25,26,28,27,

%T 29,30,32,32,34,35,37,34,36,37,39,39,41,42,44,43,45,46,48,48,50,51,53,

%U 51,53,54,56,56,58,59,61,60,62,63,65,65,67,68,70,66,68,69,71,71,73,74,76,75,77,78,80,80,82,83,85,83,85

%N a(n) = n + wt(n-1), where wt() = A000120() is the binary weight.

%C A228085(m-1) gives the number of times m occurs in this sequence.

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

%p a:= n-> n+add(i,i=Bits[Split](n-1)):

%p seq(a(n), n=1..82);  # _Alois P. Heinz_, Jul 05 2024

%t Table[n+Total[IntegerDigits[n-1,2]],{n,100}] (* _Harvey P. Dale_, May 20 2015 *)

%o (PARI) a(n) = n + hammingweight(n-1); \\ _Michel Marcus_, Jul 05 2024

%Y Cf. A000120, A092391, A228085, A230301 (complement).

%K nonn,base

%O 1,2

%A _N. J. A. Sloane_, Oct 23 2013