A141820 a(1)=1. a(n) = the smallest integer > a(n-1) that is divisible by the number of 1's in the binary representation of n.

1, 2, 4, 5, 6, 8, 9, 10, 12, 14, 15, 16, 18, 21, 24, 25, 26, 28, 30, 32, 33, 36, 40, 42, 45, 48, 52, 54, 56, 60, 65, 66, 68, 70, 72, 74, 75, 78, 80, 82, 84, 87, 88, 90, 92, 96, 100, 102, 105, 108, 112, 114, 116, 120, 125, 126, 128, 132, 135, 136, 140, 145, 150, 151, 152

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

19 in binary is 10011, which has 3 ones. a(18) = 28. Checking the integers > 28, 29 is not divisible by 3. But 30 is divisible by 3. So a(19) = 30.

Mathematica

a[1] = 1; a[n_] := a[n] = Ceiling[(a[n - 1] + 1)/(bw = DigitCount[n, 2, 1])] * bw; Array[a, 100] (* Amiram Eldar, Jul 16 2023 *)

Crossrefs

Cf. A000120, A141819.

Sequence in context: A354912 A091529 A184967 * A267137 A095775 A035063

Adjacent sequences: A141817 A141818 A141819 * A141821 A141822 A141823

Keyword

nonn,base

Author

Leroy Quet, Jul 08 2008

Extensions

Extended by Ray Chandler, Jun 21 2009

Wrong term 3 removed by Amiram Eldar, Jul 16 2023

Status

approved