A081607 Number of numbers <= n having at least one 0 in their ternary representation.

1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 5, 6, 7, 7, 7, 8, 8, 8, 9, 10, 11, 12, 12, 12, 13, 13, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 26, 26, 27, 27, 27, 28, 29, 30, 31, 31, 31, 32, 32, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 45, 45, 46, 46, 46, 47, 48, 49, 50

Offset: 0

Author

Reinhard Zumkeller, Mar 23 2003

Keywords

• nonn

Comments

a(n) + A081608(n) = n+1.

Links

• Robert Israel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A007089, A077267, A081609, A081610.

Programs

Maple

f:= n -> `if`(has(convert(n,base,3),0),1,0):
ListTools:-PartialSums(map(f, [$0..100])); # Robert Israel, Mar 18 2018

Mathematica

Accumulate[Boole[Table[DigitCount[n,3,0]>0,{n,0,80}]]] (* Harvey P. Dale, Jun 23 2017 *)

PARI

first(n)=my(s,t); vector(n,k, t=Set(digits(k,3)); s+=(t[1]==0)) \\ Charles R Greathouse IV, Sep 02 2015