21 Metaprogramming library [meta]

21.2 Compile-time integer sequences [intseq]

21.2.1 In general [intseq.general]

The library provides a class template that can represent an integer sequence.
When used as an argument to a function template the template parameter pack defining the sequence can be deduced and used in a pack expansion.
[Note 1: 
The index_sequence alias template is provided for the common case of an integer sequence of type size_t; see also [tuple.apply].
— end note]