login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A233821 Smallest zeroless number x such that x^n has exactly n zero digits. 1
245, 126, 245, 321, 351, 1244, 194, 4648, 951, 4357, 3757, 2169, 2392, 7399, 8379, 9723, 8683, 13867, 6152, 24887, 18898, 55825, 54631, 29647, 35586, 46564, 67743, 84789, 119421, 72296, 43642, 92233, 44411, 142553, 126693, 135852, 52299, 229626, 143951 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..40.

EXAMPLE

951 has no zeros and 951^10 has ten zeros (605069371210073000039238122001). This is the least positive integer with this property.

MAPLE

N:= 30: # to get terms up to a(N)

for n from 2 to N do

  for k from 1 do

     if numboccur(0, convert(k, base, 10)) = 0 and

        numboccur(0, convert(k^n, base, 10)) = n then

          A[n]:= k;

          break

     fi

  od

od:

seq(A[n], n=2..N); # Robert Israel, Aug 05 2014

PROG

(Python)

def GetNums(x):

..for n in range(10**6):

....if str(n).count("0") == 0:

......if str(n**x).count("0") == x:

........return n

x = 2

while x < 50:

..print(GetNums(x), end=', ')

..x += 1

(PARI) okxn(x, n) = {ok = 0; if (vecmin (digits(x)), dxn = digits(x^n); ok = (sum(i=1, #dxn, dxn[i] == 0) == n); ); ok; }

a(n) = {x=1; while (! okxn(x, n), x++); x; } \\ Michel Marcus, Dec 23 2013

CROSSREFS

Cf. A052382.

Sequence in context: A291587 A220090 A013684 * A216233 A157246 A186460

Adjacent sequences:  A233818 A233819 A233820 * A233822 A233823 A233824

KEYWORD

nonn,base

AUTHOR

Derek Orr, Dec 16 2013

EXTENSIONS

More terms from Michel Marcus, Dec 23 2013

Definition edited by Robert Israel, Aug 05 2014

Definition simplified by Derek Orr, Mar 23 2015

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 December 13 01:23 EST 2019. Contains 329963 sequences. (Running on oeis4.)