claim: The two most cited composites are PMOD and ACRIM.
evidence: In mathematics, a Catalan pseudoprime is an odd composite number n satisfying the congruence (  − 1  ) n − 1 2 ⋅ C n − 1 2 ≡ 2 (  mod n  ) , { \displaystyle ( -1 )^{ rac { n-1 }{ 2 } }\cdot C { rac { n-1 }{ 2 } }\equiv 2{ \pmod { n } }, } where Cm denotes the m-th Catalan number.