A030099 Numbers k such that k^3 has only odd digits.

1, 11, 15, 33, 39, 71, 91, 173, 175, 179, 211, 259, 335, 3337, 4631, 5597, 7353, 12415, 21353, 22893, 25799, 69491, 110011, 124975, 199831, 227353, 237151, 462815, 492415, 708415, 1100033, 2393695, 2620611, 5088493, 5828415, 7204417, 8320335, 11164415, 11689633

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base
• nice

Links

• Giovanni Resta, Table of n, a(n) for n = 1..563 (terms < 10^19, first 75 terms from Reinhard Zumkeller, terms 76..151 from Max Alekseyev)

Crossrefs

Cf. A000578, A030100, A034376, A052004.

Programs

Haskell

import Data.List (intersect)
a030099 n = a030099_list !! (n-1)
a030099_list = filter (null . (intersect "86420") . show . (^ 3)) [1,3..]
-- Reinhard Zumkeller, Aug 13 2011

Mathematica

fQ[n_] := Union@ OddQ@ IntegerDigits[n^3] == {True}; Select[2 Range[3*10^6] - 1, fQ] (* Robert G. Wilson v, Aug 13 2011 *)
Select[Range[12*10^6],AllTrue[IntegerDigits[#^3],OddQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Apr 14 2015 *)