A253647 -id:A253647 - cp's OEIS frontend

A124648 Numbers n such that n^i (i=1..7) are all zeroless.

1, 2, 3, 5, 6, 68, 76, 3944, 15483

Offset: 1

Zak Seidov, Dec 22 2006

No other terms < 10^8. - Michel Marcus, Oct 11 2013
No other terms < 10^13. - Charles R Greathouse IV, Oct 14 2013
Subsequence of A253647, the analog with i <= 6 instead of 7. Conjectured to be finite. - M. F. Hasler, Jan 07 2015
a(10) > 3.3*10^16, if it exists. - Giovanni Resta, Sep 06 2018

			15483^i (i=1..7) = 15483, 239723289, 3711635683587, 57467255288977521, 889765513639238957643, 13776239447676336781186569, 213297515368372722383111647827 all zeroless.

Cf. A253647, A104264, A124649.

Select[Range[10^6], FreeQ[Union[IntegerDigits[ # ],IntegerDigits[ #^2],IntegerDigits[ #^3],IntegerDigits[ #^4],IntegerDigits[ #^5],IntegerDigits[ #^6],IntegerDigits[ #^7]],0]&]
Select[Range[15500],FreeQ[Flatten[IntegerDigits/@(#^Range[7])],0]&] (* Harvey P. Dale, Jan 14 2024 *)

isok(n) = {for (i = 1, 7, if (! vecmin(digits(n^i)), return (0));); return (1);} \\ Michel Marcus, Oct 11 2013

\\ Script for checking for large (> 10^9) members:
is(n)=for(i=1,7,if(vecmin(digits(n^i))==0, return(0))); 1
bad(n,d)=for(k=1,d,if(n%10==0,return(1));n\=10);0
good7(n,d)=my(t=1);for(i=1,7,if(bad(lift(t*=n),d),return(0)));1
left(d)=my(v=List(),m=10^d);for(i=0,10^d-1, if(good7(Mod(i,m),d), listput(v,i)));Vec(v)
diff(v)=vector(#v-1,i,v[i+1]-v[i])
L=left(9);D=diff(concat(L,10^9+L[1]));forstep(n=L[1],1e12,D, if(is(n),print(n))) \\ Charles R Greathouse IV, Oct 14 2013

A252484 Numbers m such that m^k is zeroless for k=1,...,4.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 9, 11, 13, 14, 17, 21, 23, 24, 26, 27, 28, 31, 36, 39, 41, 46, 56, 58, 61, 62, 66, 68, 72, 76, 82, 83, 88, 91, 92, 96, 121, 122, 129, 137, 146, 154, 161, 162, 166, 167, 168, 183, 186, 188, 189, 211, 231, 233, 244, 256, 262, 264, 268, 277, 278, 289, 296, 337, 373, 374, 376, 382, 383

Offset: 1

M. F. Hasler, Jan 07 2015

See A253110 for the primes in this sequence. See A253644 for the subsequence including k=5.

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A052382, A253643 (k <= 3), A253644 (k <= 5), A253645 (primes, k <= 5), A253647 (k <= 6), A253646 (primes, k <= 6), A124648 (k <= 7), A124649 (k <= 8).

Cf. A104264.

filter:= proc(n)
local j;
for j from 0 to 4 do
  if has(convert(n^j,base,10),0) then return false fi
od:
true
end proc:
select(filter, [$1..1000]); # Robert Israel, Jan 15 2015

Select[Range[400],Union[DigitCount[#^Range[4],10,0]]=={0}&] (* Harvey P. Dale, Aug 01 2020 *)

is_A252484(n,K=4)=!forstep(k=K,1,-1,vecmin(digits(n^k))||return)

A253644 Numbers n such that n^k is zeroless for k=0,...,5.

Original entry on oeis.org

1, 2, 3, 5, 6, 13, 14, 17, 23, 24, 26, 31, 58, 62, 66, 68, 72, 76, 88, 96, 137, 168, 188, 233, 244, 262, 264, 296, 337, 376, 382, 383, 483, 488, 511, 514, 518, 519, 582, 628, 719, 736, 786, 816, 822, 928, 938, 971, 978, 1122, 1178, 1291, 1331, 1392, 1413, 1414, 1663, 1777

Offset: 1

M. F. Hasler, Jan 07 2015

A subsequence of A252484 (analog for k <= 4) which contains A253647 (analog including k = 6) as a subsequence. Primes in this sequence are listed in A253645.

Conjectured to be finite.

Giovanni Resta, Table of n, a(n) for n = 1..10000

Cf. A052382, A104264, A124648, A124649, A253645, A253646, A253647.

filter:= proc(x)
  local k;
  for k from 1 to 5 do
    if has(convert(x^k,base,10),0) then return false fi
  od:
  true
end proc:
select(filter, [$1..10000]); # Robert Israel, Jan 07 2015

Select[Range[2000],Count[Flatten[IntegerDigits/@(#^Range[5])],0]==0&] (* Harvey P. Dale, Jun 10 2017 *)

is_A253644(n,K=5)=!forstep(k=K,1,-1,vecmin(digits(n^k))||return)

A253646 Primes p such that p^k is zeroless for k=1,...,6.

Original entry on oeis.org

2, 3, 5, 17, 48989, 5453971, 61636943111479, 128359315177123, 884785266899689, 1116777231836989

Offset: 1

Zak Seidov and M. F. Hasler, Jan 07 2015

Primes in A253647; both sequences are conjectured to be finite.
The motivation for this sequence lies in the fact that many small primes satisfy the restriction up to k=5 (there are 52 terms below 10^6, cf. A253645), but including k=6 makes the sequence much sparser, with only one term between 17 and 5*10^6, and only one more term below 2*10^9.
The terms 2, 3 and 5 seem to be the only primes in A124648, i.e., satisfy the restriction up to k=7.
a(7) > 10^11. - Chai Wah Wu, Jan 10 2015
a(11) > 3.3*10^16. - Giovanni Resta, Sep 06 2018

Cf. A253647, A253645, A124648.

Select[Prime[Range[10^7]],Count[Flatten[IntegerDigits/@(#^Range[6])],0] == 0&] (* Harvey P. Dale, May 26 2016 *)

forprime(p=0,,forstep(k=6,1,-1,vecmin(digits(p^k))||next(2));print1(p","))

from sympy import isprime
A253646_list = [2]
for i in range(1,10**6,2):
    if not '0' in str(i):
        m = i
        for k in range(5):
            m *= i
            if '0' in str(m):
                break
        else:
            if isprime(i):
                A253646_list.append(i) # Chai Wah Wu, Jan 10 2015

a(7)-a(10) from Giovanni Resta, Sep 03 2018

A253643 Numbers n such that n^k is zeroless for k=0,...,3.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 17, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 31, 35, 36, 38, 39, 41, 44, 46, 54, 56, 57, 58, 61, 62, 65, 66, 68, 72, 75, 76, 77, 81, 82, 83, 85, 88, 91, 92, 96, 111, 113, 114, 119, 121, 122, 125, 129, 132, 133, 136, 137, 139, 146, 154, 156, 157, 158, 161

Offset: 1

M. F. Hasler, Mar 09 2015

See A252484 for the subsequence of numbers having this property up to k=4.

Cf. A052382, A252484 (k <= 4), A253644 (k <= 5), A253645 (primes, k <= 5), A253647 (k <= 6), A253646 (primes, k <= 6), A124648 (k <= 7), A124649 (k <= 8).

Cf. A104264.

Select[Range[200],AllTrue[#^Range[3],DigitCount[#,10,0]==0&]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 15 2015 *)

is_A253643(n,K=3)=!forstep(k=K,1,-1,vecmin(digits(n^k))||return)

for n in range(100):
  s1,s2,s3 = str(n),str(n**2),str(n**3)
  if s1.find('0') + s2.find('0') + s3.find('0') == -3:
    print(n,end=', ') # Derek Orr, Mar 09 2015

A358340 a(n) is the smallest n-digit number whose fourth power is zeroless.

Original entry on oeis.org

1, 11, 104, 1027, 10267, 102674, 1026708, 10266908, 102669076, 1026690113, 10266901031, 102669009704, 1026690096087, 10266900960914, 102669009608176, 1026690096080369, 10266900960803447, 102669009608034434, 1026690096080341627, 10266900960803409734, 102669009608034097731, 1026690096080340972491

Offset: 1

Mohammed Yaseen, Nov 10 2022

It has been proved that there exist infinitely many zeroless squares and cubes but there is apparently no proof for 4th powers, 5th powers, etc.

This sequence approaches the decimal expansion of 9000^(-1/4). Similar sequences of other small powers k seem to approach the decimal expansion of (9*10^(k-1))^(-1/k).

Michael S. Branicky, Table of n, a(n) for n = 1..69
Eric Weisstein's World of Mathematics, Zerofree

Cf. A052382, A052040, A052044.

Cf. A253643, A252484, A253644, A253647, A124648, A124649.

a(n) = my(x=10^(n-1)); while(! vecmin(digits(x^4)), x++); x; \\ Michel Marcus, Nov 10 2022

a(n) = { my(s = sqrtnint(10^(4*n - 3) \ 9, 4)); for(i = s, oo, c = i^4; if(vecmin(digits(c)) > 0, return(i) ) ) } \\ David A. Corneth, Nov 10 2022

from itertools import count
from sympy import integer_nthroot
def a(n):
    start = integer_nthroot(int("1"*(4*(n-1)+1)), 4)[0]
    return next(i for i in count(start) if "0" not in str(i**4))
print([a(n) for n in range(1, 22)]) # Michael S. Branicky, Nov 10 2022

a(n) ~ 10^(n + 1/4) / sqrt(3).

More terms from David A. Corneth, Nov 10 2022

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A124648 Numbers n such that n^i (i=1..7) are all zeroless.

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A252484 Numbers m such that m^k is zeroless for k=1,...,4.

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A253644 Numbers n such that n^k is zeroless for k=0,...,5.

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A253646 Primes p such that p^k is zeroless for k=1,...,6.

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A253643 Numbers n such that n^k is zeroless for k=0,...,3.

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A358340 a(n) is the smallest n-digit number whose fourth power is zeroless.

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