%I #5 Apr 03 2020 21:53:07
%S 0,0,0,1,1,4,14,130,1981,62616,2806508,158937367,10773254138,
%T 855658147832,78558952717569,8251166899386729,982806390786806618,
%U 131756175056777580011,19748565975966429686408,3289970442222058710279611,605948437043760750748781907,122796504004669690100342096563
%N Number of simple 4-regular bipartite graphs with 2n nodes.
%F Euler transform of A006824.
%Y Column k=4 of A008327.
%K nonn
%O 1,6
%A _Andrew Howroyd_, Apr 03 2020