A380193 a(n) is the largest number whose sixth power is an n-digit sixth power which has the maximum sum of digits (A373994(n)).

1, 2, 3, 4, 6, 7, 12, 19, 31, 46, 68, 96, 143, 206, 304, 461, 677, 977, 1194, 2136, 2896, 4633, 6373, 9763, 13817, 21542, 30643, 43693, 68123, 99812, 144083, 183967, 311296, 463976, 681017, 994333, 1441977, 2150104, 3022731, 4608562, 6765526, 9258023

Offset

1,2

Links

Zhining Yang, Table of n, a(n) for n = 1..55

Example

a(11) = 68 because among all 11-digit sixth powers(47^6-68^6), 64^6=68719476736 and 68^6=98867482624 have the maximum sum of digits, 96 = A373994(11) and 68 is the largest number.

Mathematica

Table[t=SortBy[Map[{#, Total@IntegerDigits[#^6]}&, Range[Ceiling[10^((n-1)/6)], Floor[(10^n-1)^(1/6)]]], Last];
Select[t, #[[2]]==t[[-1]][[2]]&][[1, 1]], {n, 36}]

Crossrefs

Cf. A370522, A373994, A379650, A379869, A380111.

Sequence in context: A039947 A339591 A380567 * A096477 A039059 A151892

Adjacent sequences: A380189 A380190 A380191 * A380194 A380197 A380198

Keyword

nonn,base,new

Author

Zhining Yang, Jan 15 2025

Status

approved