%I A072161
%S A072161 1,16,1296,10368,6480000,6480000,15558480000,124467840000,3360631680000,
%T A072161 3360631680000,49203008426880000,49203008426880000,1405287123680119680000,
%U A072161 1405287123680119680000,1405287123680119680000,11242296989440957440000
%N A072161 Denominator of Sum_{k=1..n} phi(k)/k^4.
%e A072161 1, 17/16, 1409/1296, 11353/10368, 7137097/6480000, 7147097/6480000, ...
%Y A072161 Cf. A072160.
%Y A072161 Sequence in context: A000490 A027648 A016828 this_sequence A163929 A072914 
               A007480
%Y A072161 Adjacent sequences: A072158 A072159 A072160 this_sequence A072162 A072163 
               A072164
%K A072161 nonn,frac
%O A072161 1,2
%A A072161 N. J. A. Sloane (njas(AT)research.att.com), Jun 28 2002