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A280647 Numbers k such that k^3 has an odd number of digits and the middle digit is 7. 3
31, 32, 105, 111, 128, 130, 149, 167, 173, 191, 192, 475, 483, 484, 491, 509, 524, 530, 534, 545, 546, 550, 556, 559, 584, 590, 592, 597, 614, 619, 624, 628, 637, 641, 665, 668, 692, 701, 725, 743, 750, 760, 781, 793, 809, 824, 836, 837, 843, 852, 861, 864 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence of cubes starts: 29791, 32768, 1157625, 1367631, 2097152, 2197000, 3307949, 4657463, ...

LINKS

Lars Blomberg, Table of n, a(n) for n = 1..10000

Jeremy Gardiner, Middle digit in cube numbers, Seqfan Mailing list, Dec 12 2016.

EXAMPLE

31^3 = 29(7)91, 191^3 = 696(7)871, 619^3 = 2371(7)6659

CROSSREFS

Cf. A280640-A280646, A280648-A280649, A181354.

See A279420-A279429 for a k^2 version.

See A279430-A279431 for a k^2 version in base 2.

Sequence in context: A042922 A171235 A248815 * A152045 A041479 A194380

Adjacent sequences:  A280644 A280645 A280646 * A280648 A280649 A280650

KEYWORD

nonn,base,easy

AUTHOR

Lars Blomberg, Jan 07 2017

STATUS

approved

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Last modified April 20 08:36 EDT 2019. Contains 322306 sequences. (Running on oeis4.)