For every finite abelian group $G$, there are positive integers $n$ and $d$ such that $G$ is isomorphic to the multiplicative group of $d$-th powers of reduced residues modulo $n$.
Congruences involving $\binom{4k}{2k}$ and $\binom{3k}k$
Congruences involving generalized central trinomial coefficients
Congruences involving $\binom{2k}k^2\binom{4k}{2k}m^{-k}$
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