A084661 Numbers k such that k + sum_of_digits(k) is a cube.
4, 18, 121, 198, 207, 329, 720, 977, 1318, 2183, 2731, 3357, 4082, 4891, 4900, 5814, 6836, 7969, 9243, 10634, 12154, 13797, 13806, 15611, 17554, 19656, 21929, 24367, 26973, 29759, 32746, 39281, 42853, 46629, 54850, 59292, 59301, 63968, 68890, 74070, 79475
Offset: 1
Examples
a(3)=121 because 121 + (1 + 2 + 1) = 125 = 5^3.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..250
Programs
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Mathematica
Select[Range[80000],IntegerQ[Surd[#+Total[IntegerDigits[#]],3]]&] (* Harvey P. Dale, Sep 13 2018 *)
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PARI
isok(n) = ispower(n + sumdigits(n), 3); \\ Michel Marcus, Oct 09 2013
Extensions
More terms from Michel Marcus, Oct 04 2013
Comments