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 A004092 #22 Apr 29 2023 08:10:16
%S A004092 0,2,4,6,8,1,3,5,7,9,2,4,6,8,10,3,5,7,9,11,4,6,8,10,12,5,7,9,11,13,6,
%T A004092 8,10,12,14,7,9,11,13,15,8,10,12,14,16,9,11,13,15,17,1,3,5
%N A004092 Sum of digits of even numbers.
%C A004092 a(n) >= A007953(n) / 5 with equality iff n is in A169964 (see Diophante link). - _Bernard Schott_, Apr 29 2023
%H A004092 G. C. Greubel, <a href="/A004092/b004092.txt">Table of n, a(n) for n = 0..10000</a>
%H A004092 Diophante, <a href="http://www.diophante.fr/problemes-par-themes/arithmetique-et-algebre/a1-pot-pourri/5453-a1762-des-chiffres-a-la-moulinette">A1762, Des chiffres à la moulinette</a> (in French).
%F A004092 a(n) = 2n - 9*Sum_{k=1..1+floor(log_10(2n))} floor( n/(5*10^(k-1)) ). - _Anthony Browne_, Jun 18 2016
%F A004092 a(n) = A007953(2n). - _Alois P. Heinz_, Apr 11 2018
%t A004092 Table[Sum[DigitCount[2*n][[i]]*i, {i, 9}], {n, 0, 100}] (* _G. C. Greubel_, Jun 19 2016 *)
%o A004092 (PARI) a(n)=sumdigits(2*n) \\ _Charles R Greathouse IV_, Jun 19 2016
%Y A004092 Cf. A007953, A169964.
%K A004092 nonn,base,easy
%O A004092 0,2
%A A004092 _N. J. A. Sloane_, Dec 11 1996