login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A373203
a(n) = minimum k>1 such that n^k contains all distinct decimal digits of n.
3
2, 2, 5, 5, 3, 2, 2, 5, 5, 3, 2, 2, 3, 5, 4, 6, 5, 5, 5, 7, 5, 3, 4, 7, 3, 2, 8, 2, 5, 3, 5, 4, 3, 3, 3, 6, 6, 5, 4, 3, 3, 6, 7, 4, 3, 4, 4, 4, 4, 3, 2, 3, 7, 5, 3, 2, 3, 5, 5, 3, 2, 3, 5, 2, 2, 3, 2, 3, 4, 5, 5, 3, 3, 3, 2, 3, 2, 5, 5, 5, 5
OFFSET
0,1
LINKS
FORMULA
A253600(n) <= a(n) <= A045537(n). - Michael S. Branicky, May 28 2024
A111442(n) = n^a(n).
EXAMPLE
For n=12, a(12)=3 because 12^3=1728 contains all decimal digits of n. Compare to A253600(12)=2 because 12^2=144 contains any digit of n.
MATHEMATICA
seq={}; Do[k=1; Until[ContainsAll[IntegerDigits[n^k], IntegerDigits[n] ], k++]; AppendTo[seq, k] , {n, 0, 80}]; seq
PROG
(Python)
from itertools import count
def a(n):
s = set(str(n))
return next(k for k in count(2) if s <= set(str(n**k)))
print([a(n) for n in range(81)]) # Michael S. Branicky, May 27 2024
(PARI) a(n) = my(k=2, d=Set(digits(n))); while(setintersect(Set(digits(n^k)), d) != d, k++); k; \\ Michel Marcus, Jun 01 2024
CROSSREFS
KEYWORD
nonn,base
AUTHOR
James C. McMahon, May 27 2024
STATUS
approved