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 A280646 #10 Dec 23 2024 14:53:45 %S A280646 22,25,27,36,37,124,129,134,147,156,160,169,469,497,503,527,532,540, %T A280646 547,548,549,565,571,587,602,609,652,670,672,678,688,698,713,716,722, %U A280646 735,741,746,751,754,755,789,794,797,798,805,813,820,828,849,866,883,887 %N A280646 Numbers k such that k^3 has an odd number of digits and the middle digit is 6. %C A280646 The sequence of cubes starts: 10648, 15625, 19683, 46656, 50653, 1906624, 2146689, 2406104, ... %H A280646 Lars Blomberg, <a href="/A280646/b280646.txt">Table of n, a(n) for n = 1..10000</a> %H A280646 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 A280646 22^3 = 10(6)48, 156^3 = 379(6)416, 678^3 = 3116(6)5752. %t A280646 Select[Range[887], OddQ[len=Length[IntegerDigits[#^3]]]&&Part[IntegerDigits[#^3], (len+1)/2]==6 &] (* _Stefano Spezia_, Oct 03 2023 *) %Y A280646 Cf. A280640-A280645, A280647-A280649, A181354. %Y A280646 See A279420-A279429 for a k^2 version. %Y A280646 See A279430-A279431 for a k^2 version in base 2. %K A280646 nonn,base,easy %O A280646 1,1 %A A280646 _Lars Blomberg_, Jan 07 2017