A174931 Half of the digital sum of base 3 representations of 2^n.

1, 1, 2, 2, 2, 2, 3, 2, 4, 4, 5, 5, 4, 5, 8, 6, 7, 6, 8, 7, 9, 8, 6, 5, 6, 7, 10, 10, 11, 12, 13, 12, 11, 11, 11, 9, 10, 13, 14, 14, 14, 13, 15, 15, 15, 13, 13, 13, 16, 19, 20, 19, 19, 14, 17, 20, 21, 19, 20, 23, 20, 19, 21, 24, 22, 21, 20, 21, 24, 24, 22, 21, 23, 22, 23, 23, 27, 25, 33

Offset

1,3

Links

Table of n, a(n) for n=1..79.

Example

2^4=16={1,2,1} (base 3) ==> a(4)=(1+2+1)/2 =2

Mathematica

a[n_] := 1/2* Module[{aux = IntegerDigits[2^n, 3]}, Sum[aux[[i]], {i, 1, Length[aux]}]]; Table[a[n], {n, 100}]

Crossrefs

Sequence in context: A361514 A029348 A070093 * A058744 A366297 A323246

Adjacent sequences: A174928 A174929 A174930 * A174932 A174933 A174934

Keyword

nonn,base

Author

José María Grau Ribas, Apr 02 2010

Status

approved