A152168 Number of binary digits in (n!)!.
1, 1, 2, 10, 80, 661, 5802, 54725, 558704, 6178565, 73840164, 950331113, 13121175977, 193618002604, 3042570732326, 50747501675076, 895651186352884, 16679929313440954, 326936145826028780, 6728526339596831313, 145085354333183129464, 3271200076443827203823
Offset: 0
Examples
(3!)! = 6! = 720 has ten binary digits (1011010000), so a(3) = 10.
Links
Programs
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PARI
a(n) = length(binary(n!!)) \\ Michel Marcus, Jun 02 2013