%I A050521
%S A050521 1,1,1,3,1,7,1,10,4,7,1,33,1,7,9,28,1,39,1,33
%N A050521 Number of factorizations of (n,2*n) into pairs (k,l).
%C A050521 Pairs (k,l) must satisfy 0<k, 0<l; if k=1 then l=1. Definition of "*": 
               (a,b)*(x,y)=(a*x,b*y); unit is (1,1).
%e A050521 (10,20) = (2,1)*(5,20) = (2,20)*(5*1) = (2,2)*(5,10) = (2,10)*(5,2) = 
               (2,4)*(5,5) = (2,5)*(5,4); so a(10) = 7.
%Y A050521 Cf. A051707.
%Y A050521 Sequence in context: A099749 A077202 A086665 this_sequence A098093 A114712 
               A089741
%Y A050521 Adjacent sequences: A050518 A050519 A050520 this_sequence A050522 A050523 
               A050524
%K A050521 nonn,nice,easy,more
%O A050521 1,4
%A A050521 Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)