login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A147884 a(n) is the smallest positive integer k such that the last n digits of 2^k are 1 or 2. 0
1, 9, 89, 89, 589, 3089, 3089, 3089, 315589, 315589, 8128089, 164378089, 945628089, 1922190589, 11687815589, 109344065589, 231414378089, 1452117503089, 4503875315589, 65539031565589, 141832976878089, 1667711883128089 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..22.

FORMULA

a(n) = the smallest degree k such that 2^k == A053312(n) (mod 5^n)

PROG

(PARI) { m=2; for(n=1, 50, print1(znlog(m, Mod(2, 5^n)), ", "); m+=10^n; if(m%(2^(n+1)), m+=10^n); ) }

CROSSREFS

Cf. A053312

Sequence in context: A084015 A231155 A279166 * A178369 A328492 A306686

Adjacent sequences:  A147881 A147882 A147883 * A147885 A147886 A147887

KEYWORD

base,easy,nonn

AUTHOR

Max Alekseyev, Nov 17 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 19 06:18 EST 2022. Contains 350464 sequences. (Running on oeis4.)