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 A152168 #16 Oct 27 2021 21:52:54 %S A152168 1,1,2,10,80,661,5802,54725,558704,6178565,73840164,950331113, %T A152168 13121175977,193618002604,3042570732326,50747501675076, %U A152168 895651186352884,16679929313440954,326936145826028780,6728526339596831313,145085354333183129464,3271200076443827203823 %N A152168 Number of binary digits in (n!)!. %H A152168 Jon E. Schoenfield, <a href="/A152168/b152168.txt">Table of n, a(n) for n = 0..30</a> %H A152168 <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a> %e A152168 (3!)! = 6! = 720 has ten binary digits (1011010000), so a(3) = 10. %o A152168 (PARI) a(n) = length(binary(n!!)) \\ _Michel Marcus_, Jun 02 2013 %Y A152168 Cf. A000197, A072831. %K A152168 base,nonn %O A152168 0,3 %A A152168 _Jon E. Schoenfield_, Nov 27 2008