cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A155881 a(n) is the number of zeros needed to write the integers 1 through Fibonacci(n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 2, 3, 5, 8, 24, 43, 67, 121, 188, 409, 708, 1228, 1946, 4131, 6241, 10525, 17866, 29428, 58369, 87881, 156261, 255242, 412545, 767846, 1280460, 2059307, 3343656, 5510186, 9861418, 16472261, 26422596, 43917688, 73697381, 125281166, 206655249
Offset: 1

Views

Author

Avik Roy (avik_3.1416(AT)yahoo.co.in), Jan 29 2009

Keywords

Comments

Data suggets a(n) ~= 10 ^ (c * n) where c ~= 0.209. - David A. Corneth, Jan 23 2019

Examples

			F(9)=34, so writing the numbers F(1)..F(9) requires 3 zeros (one each at 10, 20, and 30), thus a(9)=3.
		

Crossrefs

Programs

  • Maple
    A055641 := proc(n) option remember ; local a,d; if n = 0 then RETURN(a) ; fi; a := 0 ; for d in convert(n,base,10) do if d = 0 then a := a+1 ; fi; od: a ; end: A155881 := proc(n) add(A055641(i),i=1..combinat[fibonacci](n)) ; end: for n from 1 do printf("%d,\n",A155881(n)) ; od; # R. J. Mathar, Feb 19 2009
  • Mathematica
    Block[{n = 32, s}, s = DigitCount[Range@ Fibonacci@ n, 10, 0]; Array[Total@ Take[s, Fibonacci@ #] &, n]] (* Michael De Vlieger, Jan 23 2019 *)
  • PARI
    nb(n) = #Set(select(x->(x==0), digits(n))); \\ A055641
    a(n) = sum(k=1, fibonacci(n), nb(k)); \\ Michel Marcus, Jan 23 2019
    
  • PARI
    a(n) = my(n = fibonacci(n), m=logint(n, 10)); (m+1)*(n+1) - (10^(m+1)-1)/9 + (1/2) * sum(j=1, m+1, (n\10^j * (2*n+2 - (1 + n\10^j) * 10 ^ j) - floor(n/10^j+9/10) * (2*n+2 + ((4/5 - floor(n / 10^j + 9 / 10))*10^j)))) \\ David A. Corneth, Jan 23 2019

Formula

a(n) = A061217(Fibonacci(n)) = A061217(A000045(n)). - David A. Corneth, Jan 23 2019

Extensions

8 more terms from R. J. Mathar, Feb 19 2009
9 more terms from Sean A. Irvine, Dec 10 2009
Edited by Jon E. Schoenfield, Jan 22 2019
More terms from David A. Corneth, Jan 23 2019