Decomposable numbers as ghost orders
Prove or disprove that every decomposable positive integer is a ghost order, meaning that no finite group of that order has an endopure subgroup.
References
However, given the computational evidence one would conjecture that every decomposable number is a ghost order.
— Global transfer systems and endopurity of subgroups
(2610.22141 - Balchin et al., 15 Oct 2026) in Remark 'Ghost orders', Section 5.4