linear algebra: find the analytical form of the eigenvalue of a special dispersed matrix

Leave $ hat { bf H} $ be a $ p hat {N} times p hat {N} $ scattered matrix consisting of $ p times p $ blocks, where each block is in size $ hat {N} times hat {N} $. The values ​​in $ hat { bf H} $ is illustrated below (empty places are zero):

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Ask for help in finding the analytical form of eigenvalues ​​(especially the largest eigenvalue) of this matrix.