claim: "So  recently the media picked up on the fact that CRU deleted the raw data for this  important global temperature set long ago.
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)^{\frac {n-1}{2}}\cdot C_{\frac {n-1}{2}}\equiv 2{\pmod {n}},} where Cm denotes the m-th Catalan number.