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A280643
Numbers k such that k^3 has an odd number of digits and the middle digit is 3.
3
29, 34, 39, 46, 118, 125, 141, 142, 155, 161, 170, 211, 213, 477, 489, 511, 522, 526, 529, 535, 554, 573, 582, 586, 589, 631, 632, 633, 645, 663, 680, 691, 699, 723, 733, 744, 747, 770, 785, 790, 816, 817, 832, 854, 859, 863, 869, 873, 878, 892, 897, 901, 923
OFFSET
1,1
COMMENTS
The sequence of cubes starts: 24389, 39304, 59319, 97336, 1643032, 1953125, 2803221, 2863288, ...
LINKS
Jeremy Gardiner, Middle digit in cube numbers, Seqfan Mailing list, Dec 12 2016.
EXAMPLE
29^3 = 24(3)89, 161^3 = 417(3)281, 663^3 = 2914(3)4247.
MATHEMATICA
Select[Range[925], OddQ[len=Length[IntegerDigits[#^3]]]&&Part[IntegerDigits[#^3], (len+1)/2]==3 &] (* Stefano Spezia, Oct 03 2023 *)
CROSSREFS
See A279420-A279429 for a k^2 version.
See A279430-A279431 for a k^2 version in base 2.
Sequence in context: A295153 A031172 A159022 * A102527 A039307 A043130
KEYWORD
nonn,base,easy
AUTHOR
Lars Blomberg, Jan 07 2017
STATUS
approved