  Let k and n be positive even integers. For a cuspidal Hecke eigenform h in
the Kohnen plus space of weight k-n/2+1/2, let f be the corresponding primitive
form of weight 2k-n for SL(2,Z) under the Shimura correspondence, and I(h) the
Duke-Imamoglu-Ikeda lift of h to the space of cusp forms of weight k of genus
n. Moreover, let FJ(I(h),1) be the first Fourier-Jacobi coefficient of I(h) and
s(FJ(I(h),1)) be the cusp form in the generalized Kohnen plus space of weight
k-1/2 corresponding to FJ(I(h),1) under the Ibukiyama isomorphism. We then give
an explicit formula for the Koecher-Maass series of s(FJ(I(h),1)) expressed in
terms of the usual L-functions of h and f.
