This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A234967 Smallest zeroless number such that a(n)^n has at least one zero. 0
 32, 16, 7, 4, 4, 8, 5, 6, 2, 2, 2, 4, 5, 3, 3, 2, 3, 4, 2, 2, 2, 2, 4, 3, 2, 4, 4, 2, 2, 4, 3, 3, 4, 3, 3, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS It is very probable that a(n) = 2 for n > 87. LINKS EXAMPLE 7 is the smallest number with nonzero digits such that 7^4 has at least one zero, so a(4) = 7. MATHEMATICA m[n_] := Min@ IntegerDigits@n; a[1]=0; a[n_] := Block[{k=2}, While[m[k] == 0 || m[k^n] > 0, k++]; k]; Array[a, 70] (* Giovanni Resta, Jan 11 2014 *) PROG (Python) def f(x): ..for n in range(10**7): ....if str(n).find("0") == -1: ......if str(n**x).find("0") > -1: ........return n x = 1 while x < 75: ..if f(x) == None: ....print(0) ..else: ....print(f(x)) ..x += 1 CROSSREFS Cf. A052382. Sequence in context: A097614 A069892 A070621 * A033352 A140387 A023094 Adjacent sequences:  A234964 A234965 A234966 * A234968 A234969 A234970 KEYWORD nonn,base AUTHOR Derek Orr, Jan 02 2014 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.

Last modified October 20 22:44 EDT 2019. Contains 328291 sequences. (Running on oeis4.)