- In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called elements, or terms). The number of elements (possibly infinite) is called the length of the sequence. Unlike a set, the same elements can appear multiple times at different positions in a sequence, and unlike a set, the order does matter. Formally, a sequence can be defined as a function from natural numbers (the positions of elements in the sequence) to the elements at each position. The notion of a sequence can be generalized to an indexed family, defined as a function from an arbitrary index set.
- Psilocybe cubensis (Wikipedia)
Psilocybe cubensis is a species of psilocybin mushroom of moderate potency whose principal active compounds are psilocybin and psilocin. Commonly called shrooms, magic mushrooms, golden halos, cubes, or gold caps, it belongs to the fungus family Hymenogastraceae and was previously known as Stropharia cubensis. It is the best-known psilocybin mushroom due to its wide distribution and ease of cultivation. This mushroom being optimal for home cultivation specifically, as was suggested in the 1970s, is primarily what led to cubensis being the psilocybin mushroom species most common on the black market as a street drug.