login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A063580 Smallest k such that 4^k has exactly n 5's in its decimal representation. 1
1, 4, 8, 37, 38, 34, 72, 54, 71, 89, 99, 136, 105, 134, 151, 172, 206, 159, 202, 214, 156, 304, 274, 278, 253, 281, 268, 358, 326, 375, 389, 345, 424, 429, 460, 488, 449, 484, 466, 521, 531, 544, 568, 556, 638, 540, 590, 547, 508, 677, 606 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..50.

MATHEMATICA

a = {}; Do[k = 1; While[ Count[ IntegerDigits[4^k], 5] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

With[{c=4^Range[700]}, Flatten[IntegerExponent[#, 4]&/@Table[Select[c, DigitCount[#, 10, 5] == n&, 1], {n, 0, 50}]]] (* Harvey P. Dale, Nov 06 2013 *)

CROSSREFS

Sequence in context: A229535 A309618 A047710 * A003049 A098563 A231398

Adjacent sequences:  A063577 A063578 A063579 * A063581 A063582 A063583

KEYWORD

base,nonn

AUTHOR

Robert G. Wilson v, Aug 10 2001

EXTENSIONS

Name corrected by Jon E. Schoenfield, Jun 26 2018

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 July 5 20:21 EDT 2020. Contains 335473 sequences. (Running on oeis4.)