

A123756


a(0)=0. a(n) = number of earlier terms which are divisible by (the number of 1's in the binary representation of n).


1



0, 1, 2, 2, 4, 4, 5, 1, 8, 6, 7, 2, 8, 2, 2, 5, 16, 12, 13, 3, 13, 4, 4, 9, 15, 6, 7, 9, 8, 10, 10, 6, 32, 21, 21, 11, 21, 12, 13, 12, 23, 14, 14, 13, 14, 13, 13, 6, 27, 16, 16, 15, 17, 15, 15, 9, 20, 16, 17, 10, 17, 11, 11, 8, 64, 34, 35, 20, 36, 21, 22, 21, 38, 23, 23, 21, 24, 22, 22, 13
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OFFSET

0,3


LINKS

Table of n, a(n) for n=0..79.


EXAMPLE

9 in binary is 1001, which has 2 ones. So a(9) is the number of terms, from a(0) to a(8), which are divisible by 2. a(0)=0, a(2)=2, a(3)=2, a(4)=4, a(5)=4 and a(8)=8 are the six earlier terms which are divisible by 2. So a(9) = 6.


MATHEMATICA

f[l_List] := Append[l, Count[Mod[l, Plus @@ IntegerDigits[Length[l], 2]], 0]]; Nest[f, {0}, 80] (*Chandler*)


CROSSREFS

Cf. A123755.
Sequence in context: A284432 A284435 A156130 * A300755 A307825 A116648
Adjacent sequences: A123753 A123754 A123755 * A123757 A123758 A123759


KEYWORD

easy,nonn


AUTHOR

Leroy Quet, Oct 12 2006


EXTENSIONS

Extended by Ray Chandler, Oct 16 2006


STATUS

approved



