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A280644
Numbers k such that k^3 has an odd number of digits and the middle digit is 4.
3
7, 104, 112, 140, 143, 158, 166, 186, 188, 195, 465, 467, 490, 541, 558, 572, 595, 598, 604, 605, 606, 607, 613, 616, 622, 625, 630, 634, 635, 640, 643, 647, 653, 667, 675, 679, 687, 702, 712, 718, 720, 727, 734, 738, 759, 764, 783, 787, 802, 810, 815, 818
OFFSET
1,1
COMMENTS
The sequence of cubes starts: 343, 1124864, 1404928, 2744000, 2924207, 3944312, 4574296, 6434856, ...
LINKS
Jeremy Gardiner, Middle digit in cube numbers, Seqfan Mailing list, Dec 12 2016.
EXAMPLE
7^3 = 3(4)3, 195^3 = 741(4)875, 640^3 = 2621(4)4000
MATHEMATICA
Select[Range[1000], OddQ[IntegerLength[#^3]]&&NumberDigit[#^3, (IntegerLength[ #^3]-1)/2]==4&] (* Harvey P. Dale, Aug 12 2021 *)
CROSSREFS
See A279420-A279429 for a k^2 version.
See A279430-A279431 for a k^2 version in base 2.
Sequence in context: A318398 A318815 A195246 * A322646 A224706 A001921
KEYWORD
nonn,base,easy
AUTHOR
Lars Blomberg, Jan 07 2017
STATUS
approved