This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A280648 #11 Dec 23 2024 14:53:45 %S A280648 2,24,35,38,120,127,131,138,145,172,174,182,183,208,212,215,471,481, %T A280648 482,485,495,505,516,517,544,551,567,594,601,610,617,621,644,646,674, %U A280648 677,689,736,739,749,756,768,773,774,775,776,786,799,803,812,821,830,835 %N A280648 Numbers k such that k^3 has an odd number of digits and the middle digit is 8. %C A280648 The sequence of cubes starts: 8, 13824, 42875, 54872, 1728000, 2048383, 2248091, 2628072, ... %H A280648 Lars Blomberg, <a href="/A280648/b280648.txt">Table of n, a(n) for n = 1..10000</a> %H A280648 Jeremy Gardiner, <a href="https://web.archive.org/web/*/http://list.seqfan.eu/oldermail/seqfan/2016-December/017135.html">Middle digit in cube numbers</a>, Seqfan Mailing list, Dec 12 2016. %e A280648 2^3 = (8), 172^3 = 508(8)448, 610^3 = 2269(8)1000. %t A280648 Select[Range[835], OddQ[len=Length[IntegerDigits[#^3]]]&&Part[IntegerDigits[#^3], (len+1)/2]==8 &] (* _Stefano Spezia_, Oct 03 2023 *) %Y A280648 Cf. A280640-A280647, A280649, A181354. %Y A280648 See A279420-A279429 for a k^2 version. %Y A280648 See A279430-A279431 for a k^2 version in base 2. %K A280648 nonn,base,easy %O A280648 1,1 %A A280648 _Lars Blomberg_, Jan 07 2017