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 A048288 #14 Sep 04 2021 09:57:08
%S A048288 0,2,2,2,3,2,2,4,5,3,2,3,3,4,6,4,7,10,4,5,4,5,4,5,6,9,9,5,7,8,3,6,5,7,
%T A048288 9,8,4,3,6,5,8,6,3,8,7,5,7,7,3,6,3,7,12,14,3,5,4,6,3,3,5,9,6,6,7,7,4,
%U A048288 8,8,4,9,5,7,8,10,3,7,6,4,9,10,1,3,8,3
%N A048288 Number of prime factors counted with multiplicity of the reverse concatenation of numbers from 1 to n.
%H A048288 Sean A. Irvine, <a href="/A048288/b048288.txt">Table of n, a(n) for n = 1..106</a>
%H A048288 Patrick De Geest, <a href="http://www.worldofnumbers.com/revfact.htm">Reversed Smarandache Concatenated Numbers</a>
%H A048288 M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/michafleuren.htm">Factors and primes of Smarandache sequences</a>.
%H A048288 M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/micha.txt">Smarandache Factors and Reverse factors</a>
%H A048288 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_008.htm">Puzzle 8. Primes by Listing</a>, The Prime Puzzles and Problems Connection.
%F A048288 a(n) = A001222(A000422(n)). - _Michel Marcus_, Jun 14 2021
%e A048288 21 = 3*7 so a(2) = 2; 321 = 3*107 so a(3) = 2; 4321 = 29*149 so a(4) = 2; etc.
%e A048288 a(1)=0 since 1 has no prime factors.
%t A048288 Join[{0},Table[PrimeOmega[FromDigits[Flatten[IntegerDigits[Range[i,1,-1]]]]],{i,2,36}]] (* _Jayanta Basu_, May 30 2013 *)
%Y A048288 Cf. A000422, A001222, A046460, A046461, A046468, A050679, A050680, A050681, A050682.
%K A048288 nonn,base
%O A048288 1,2
%A A048288 Paul Jasper (jasperpaul(AT)hotmail.com)
%E A048288 Offset and a(19) corrected and more terms from _Sean A. Irvine_, Jun 13 2021
%E A048288 Edited by _N. J. A. Sloane_, Sep 04 2021