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A243975 Least number k such that 3^k contains exactly n identical digits. 2
1, 8, 11, 29, 32, 47, 34, 33, 90, 98, 112, 136, 128, 172, 111, 168, 146, 211, 241, 218, 220, 290, 278, 298, 323, 355, 329, 316, 344, 446, 427, 395, 410, 528, 481, 443, 498, 523, 574, 540, 531, 538, 618, 549, 694, 669, 733, 717, 788, 707, 740, 734, 831, 743, 857, 850, 864 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

It is permissible for 3^k to have more than one digit repeated n times.  For example a(11)=112, and 3^112 has 11 digits equal to 3 and also 11 digits equal to 7. - Harvey P. Dale, Feb 19 2015

LINKS

Table of n, a(n) for n=1..57.

Index entries for sequences related to decimal expansion of n

EXAMPLE

3^11 = 177147 contains 3 of the same digit (7). Since 11 is the smallest power of 3 to do this, a(3) = 11.

MAPLE

N:= 1000: # to get a(1) to a(m-1) where a(m) is the first > N

f:= proc(k)

  local L;

  L:= convert(3^k, base, 10);

  max(seq(numboccur(i, L), i=0..9));

end proc:

for k from 1 to N do

  v:= f(k);

  if not assigned(A[v]) then A[v]:= k fi;

od:

for m from 1 while assigned(A[m]) do od:

seq(A[i], i=1..m-1); # Robert Israel, Feb 19 2015

MATHEMATICA

lnk[n_]:=Module[{k=1}, While[Count[DigitCount[3^k], n]<1, k++]; k]; Array[ lnk, 60] (* Harvey P. Dale, Feb 19 2015 *)

PROG

(Python)

def b():

..n = 1

..k = 1

..while k < 50000:

....st = str(3**k)

....if len(st) >= n:

......for a in range(10):

........count = 0

........for i in range(len(st)):

..........if st[i] == str(a):

............count += 1

........if count == n:

..........print(k, end=', ')

..........n += 1

..........k = 0

..........break

......k += 1

....else:

......k += 1

b()

CROSSREFS

Cf. A000244, A243972.

Sequence in context: A053701 A029615 A051791 * A160796 A160416 A056873

Adjacent sequences:  A243972 A243973 A243974 * A243976 A243977 A243978

KEYWORD

nonn,base

AUTHOR

Derek Orr, Jun 16 2014

STATUS

approved

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Last modified September 16 12:57 EDT 2019. Contains 327113 sequences. (Running on oeis4.)