Haskell, 268 bytes

f d=(iterate (\(b,e)->r(\(x,y)(z,w)->(x*10^(2*d-y)+z*10^(2*d-w),2*d))(0,0)$takeWhile((/=0).fst)[r(\(x,y)(z,w)->(x*z,y+w))((-1)^n,0)[let z=2*e*n;s=max(z-d)0in(b^(2*n)`div`10^s,z-s),(10^d`div`product[2..2*n],d)]|n<-[0..]])(7,1))#[];(h:t)#v|h`elem`v=h|0<1=t#(h:v);r=foldr

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It probably won't win any award for length; but does include a (quite rudimentary) implementation of arbitrary precision math.

Haskell, 267 bytes

f d=(iterate(\(b,e)->r(\(x,y)(z,w)->(x*10^(2*d-y)+z*10^(2*d-w),2*d))(0,0)$takeWhile((/=0).fst)[r(\(x,y)(z,w)->(x*z,y+w))((-1)^n,0)[let z=2*e*n;s=max(z-d)0in(b^(2*n)`div`10^s,z-s),(10^d`div`product[2..2*n],d)]|n<-[0..]])(7,1))#[];(h:t)#v|h`elem`v=h|0<1=t#(h:v);r=foldr

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