A280646 - OEIS

A280646

Numbers k such that k^3 has an odd number of digits and the middle digit is 6.

22, 25, 27, 36, 37, 124, 129, 134, 147, 156, 160, 169, 469, 497, 503, 527, 532, 540, 547, 548, 549, 565, 571, 587, 602, 609, 652, 670, 672, 678, 688, 698, 713, 716, 722, 735, 741, 746, 751, 754, 755, 789, 794, 797, 798, 805, 813, 820, 828, 849, 866, 883, 887

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

The sequence of cubes starts: 10648, 15625, 19683, 46656, 50653, 1906624, 2146689, 2406104, ...

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

22^3 = 10(6)48, 156^3 = 379(6)416, 678^3 = 3116(6)5752.

MATHEMATICA

Select[Range[887], OddQ[len=Length[IntegerDigits[#^3]]]&&Part[IntegerDigits[#^3], (len+1)/2]==6 &] (* Stefano Spezia, Oct 03 2023 *)

CROSSREFS

Cf. A280640-A280645, A280647-A280649, A181354.

See A279420-A279429 for a k^2 version.

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

Sequence in context: A061371 A254753 A070809 * A345479 A295799 A338603

Adjacent sequences: A280643 A280644 A280645 * A280647 A280648 A280649

KEYWORD

nonn,base,easy

AUTHOR

Lars Blomberg, Jan 07 2017

STATUS

approved

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