A239465 a(n) is the least k such that e(k) = n, where e(k) is the smallest m > 1 such that k^m contains all the digits of k with at least the same multiplicity.

1, 4, 14, 2, 15, 19, 26, 118, 128, 1388, 18588, 111143, 11721111115

Offset

2,2

Comments

10^12 < a(15) <= 33333333333338.

Links

Table of n, a(n) for n=2..14.

Example

a(3) = 4 because e(1) = 2 (1^2 = 1), e(2) = 5 (2^5 = 32), e(3) = 5 (3^5 = 243) and finally e(4) = 3 (4^3 = 64).

Mathematica

e[k_] := Block[{m=2, d = DigitCount@k}, While[Min[DigitCount[k^m] - d] < 0, m++]; m]; a[n_] := Block[{k=1}, While[e[k] != n, k++]; k]; a /@ Range[2, 11]

Crossrefs

Sequence in context: A182441 A107775 A003117 * A375925 A156985 A138229

Adjacent sequences: A239462 A239463 A239464 * A239466 A239467 A239468

Keyword

nonn,base,hard,more

Author

Giovanni Resta, Mar 19 2014

Status

approved