A020666 a(n)^n is the least n-th power containing every digit.

1023456789, 32043, 2326, 763, 309, 159, 56, 104, 49, 36, 25, 15, 25, 17, 17, 15, 16, 7, 5, 6, 6, 5, 11, 9, 14, 5, 5, 5, 5, 9, 5, 8, 11, 4, 4, 6, 5, 7, 3, 5, 4, 4, 6, 4, 3, 6, 3, 3, 4, 4, 5, 4, 3, 6, 4, 4, 3, 4, 4, 3, 3, 3, 3, 3, 3, 4, 3, 2, 3, 2, 3, 3, 3, 3, 4, 3, 3, 3, 2, 3, 4, 2, 3, 2, 3, 3, 2, 2, 2

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• base

Comments

It is extremely probable that a(n) = 2 for all n >= 169.

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A020667, A112388, A137214.

Programs

Python

def a(n):
    if n == 1: return 1023456789
    an = 2
    while not(len(set(str(an**n))) == 10): an += 1
    return an
print([a(n) for n in range(1, 90)]) # Michael S. Branicky, Jul 04 2021