%I A035483
%S A035483 1,1,4,456,10936320
%N A035483 2n X 2n symmetric matrices whose first row is 1..2n and whose rows and 
               columns are all permutations of 1..2n.
%Y A035483 Cf. A000438, A035481, A000315, A002860, A003090, A040082.
%Y A035483 Sequence in context: A159514 A034985 A104690 this_sequence A145570 A053292 
               A053963
%Y A035483 Adjacent sequences: A035480 A035481 A035482 this_sequence A035484 A035485 
               A035486
%K A035483 more,nonn,nice
%O A035483 0,3
%A A035483 Joshua Zucker and Joe Keane (joshua.zucker(AT)stanfordalumni.org)