%I A074787
%S A074787 1,5,9,13,17,33,37,41,45,61,65,81,85,101,117,121,125,141,145,161,177,
%T A074787 193,197,213,217,233,237,253,257,321,325,329,345,361,377,393,397,413,
%U A074787 429,445,449,513,517,533,549,565,569,585,589,605,621,637,641,657,673
%N A074787 Sum of squares of the number of unitary divisors of k from 1 to n.
%F A074787 a(n)= Sum_{k=1..n} ud(k)^2 = Sum_{k=1..n} A034444(k)^2 . a(n) = Sum_{k=1..n} 
               2^(2*omega(k)) = Sum_{k=1..n} 2^(2*A001221(k)).
%p A074787 with(numtheory): seq(add(2^(2*nops(ifactors(k)[2])),k=1..n),n=1..100);
%Y A074787 Cf. A034444, A064608.
%Y A074787 Equals 4*A069811(n) + 1.
%Y A074787 Sequence in context: A085759 A032493 A125018 this_sequence A079497 A081835 
               A088907
%Y A074787 Adjacent sequences: A074784 A074785 A074786 this_sequence A074788 A074789 
               A074790
%K A074787 nonn
%O A074787 1,2
%A A074787 Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Sep 07 2002