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Number of decimal digits in (10^n)!!.
0

%I #7 Aug 15 2015 10:06:57

%S 1,4,80,1285,17831,228289,2782857,32828532,378285281,4282852764,

%T 47828527596,528285275911,5782852759055,62828527590491,

%U 678285275904845,7282852759048382,77828527590483750

%N Number of decimal digits in (10^n)!!.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/DoubleFactorial.html">Double Factorial</a>

%Y Cf. A006882.

%K nonn,base

%O 0,2

%A _Eric W. Weisstein_, Nov 30 2005