OFFSET
0,2
COMMENTS
The asymptotic density of this sequence is log_10(2) = 0.301029... (A007524). - Amiram Eldar, Jan 27 2021
LINKS
Muniru A Asiru, Table of n, a(n) for n = 0..5000
FORMULA
a(n) = ceiling(n*log_2(10)). - Vladeta Jovovic, Jun 20 2002
a(n) = log_2(A067488(n+1)). - Charles L. Hohn, Jun 09 2024
MATHEMATICA
a[n_] := Block[{k = 0}, While[ Floor[Log[10, 2^k] + 1] < n, k++ ]; k]; Table[ a[n], {n, 1, 61}]
Table[Ceiling[n*Log[2, 10]], {n, 0, 59}] (* Jean-François Alcover, Jan 29 2014, after Vladeta Jovovic *)
PROG
(PARI) for(n=0, 500, if(floor(2^n/10^(floor(n*log(2)/log(10))))==1, print1(n, ", ")))
(PARI) a(n) = ceil(n*log(10)/log(2)); \\ Michel Marcus, May 13 2017
(GAP) Filtered([0..200], n->ListOfDigits(2^n)[1]=1); # Muniru A Asiru, Oct 22 2018
(Python)
def A067497(n): return (10**n-1).bit_length() # Chai Wah Wu, Apr 02 2023
(Sage) [ceil(n*log(10)/log(2)) for n in range(0, 60)] # Stefano Spezia, Aug 31 2024
CROSSREFS
KEYWORD
base,nonn,easy
AUTHOR
Benoit Cloitre, Feb 22 2002
EXTENSIONS
Additional comments from Lekraj Beedassy, Jun 20 2002 and from Rick Shephard, Jun 27 2002
STATUS
approved