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 A099550 #11 Aug 29 2024 09:15:58
%S A099550 1,1,3,1,5,3,7,1,0,5,2,3,4,7,6,1,8,0,1,5,3,2,5,3,7,4,0,7,2,6,4,1,6,8,
%T A099550 8,0,1,1,3,5,5,3,7,2,0,5,2,3,4,7,6,4,8,0,1,7,3,2,5,6,7,4,0,1,2,6,4,8,
%U A099550 6,8,8,0,1,1,3,1,5,3,7,5,0,5,2,3,4,7,6,2,8,0,1,5,3,2,5,3,7,4,0,7,2,6
%N A099550 Odd part of n modulo 9.
%H A099550 Amiram Eldar, <a href="/A099550/b099550.txt">Table of n, a(n) for n = 1..10000</a>
%F A099550 a(n) = A010878(A000265(n)).
%F A099550 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 4. - _Amiram Eldar_, Aug 29 2024
%t A099550 a[n_] := Mod[n / 2^IntegerExponent[n, 2], 9]; Array[a, 100] (* _Amiram Eldar_, Aug 29 2024 *)
%o A099550 (PARI) a(n) = (n>>valuation(n, 2))%9 \\_Charles R Greathouse IV_, May 14 2014
%Y A099550 Cf. A000265, A010878.
%Y A099550 Cf. A099544, A099545, A099546, A099547, A099548, A099549, A099551.
%K A099550 nonn,easy
%O A099550 1,3
%A A099550 _Ralf Stephan_, Oct 23 2004