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 A253274 #17 Mar 27 2023 03:38:43
%S A253274 1,0,2,0,3,0,3,2,3,5,3,6,2,12,3,13,3,9,6,13,10,9,7,13,9,13,5,14,6,12,
%T A253274 11,26,0,14,15,17,6,20,15,18,17,35,10,8,23,11,15,10,16,29,32,12,19,27,
%U A253274 25,26,18,24,33,22,36,13,24,18,24,43,16,29,35,18,12,42
%N A253274 Exponent of the highest power of 2 dividing A007497(n).
%H A253274 Amiram Eldar, <a href="/A253274/b253274.txt">Table of n, a(n) for n = 1..1500</a>
%F A253274 a(n) = A007814(A007497(n)).
%e A253274 A007497(9) = 168 = 2^3*3*7, so a(n) = 3.
%t A253274 f[1] = 2; f[n_] := f[n] = DivisorSigma[1, f[n - 1]]; Table[IntegerExponent[f[n], 2], {n, 70}] (* _Amiram Eldar_, Mar 27 2023 *)
%Y A253274 Cf. A007497, A007814.
%K A253274 nonn
%O A253274 1,3
%A A253274 _Allan C. Wechsler_, May 01 2015
%E A253274 More terms from _Michel Marcus_, May 01 2015