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 A046462 #28 Oct 01 2023 07:35:32 %S A046462 2,5,10,13,14,15,31,51,61,67,73 %N A046462 Numbers k such that the concatenation of numbers from 1 to k is the product of 3 primes (not necessarily distinct). %H A046462 Patrick De Geest, <a href="http://www.worldofnumbers.com/factorlist.htm">Normal Smarandache Concatenated Numbers, Prime factors from 1 up to n</a> %H A046462 M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/michafleuren.htm">Factors and primes of Smarandache sequences</a>. %H A046462 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_008.htm">Puzzle 8. Primes by Listing</a>, The Prime Puzzles & Problems Connection. %F A046462 A046460(a(n)) = 3. %p A046462 q:= n-> is(numtheory[bigomega](parse(cat($1..n)))=3): %p A046462 select(q, [$1..35])[]; # _Alois P. Heinz_, Apr 10 2021 %t A046462 Select[Range[100], %t A046462 PrimeOmega@FromDigits@Flatten@IntegerDigits@Range@# == 3 &] (* _Robert Price_, Oct 11 2019 *) %Y A046462 Cf. A001222, A046460. %K A046462 nonn,hard,base %O A046462 1,1 %A A046462 _Patrick De Geest_, Aug 15 1998 %E A046462 a(10)-a(11) from _Sean A. Irvine_, Apr 10 2021