The number of identity elements of length n in Z*Z^2.

Terms

a(0) =1a(1) =0a(2) =6a(3) =0a(4) =74a(5) =0a(6) =1140a(7) =0a(8) =19562a(9) =0a(10) =357756a(11) =0a(12) =6824684a(13) =0a(14) =134166696a(15) =0a(16) =2697855082a(17) =0a(18) =55213424556a(19) =0a(21) =0a(23) =0a(25) =0a(27) =0a(29) =0a(31) =0a(33) =0