# Permutations and partitions in the OEIS This article referencessequences from the OEIS.

Permutations of a finite set are often sorted lexicographically, but reverse colexicographical order gives an infinite order of finite permutations.
(In this order the inversion vector of the n-th permutation interpreted as a factorial number is n.)
The finite permutations are stored as rows of a triangle in A055089.

Partitions of a finite set and partitions of an integer are also often ordered lexicographically, but the sequences A231428 and A194602 define an infinite order.

These infinite orderings make it possible to define some mappings as sequences:

Each permutation corresponds to a set partition (A249618), and more importantly to an integer partition (A198380) called its cycle type.
(A set partition corresponds only to a finite number of permutations, but each cycle type > 0 corresponds to an infinite number of permutations.)
Each set partition corresponds to an integer partition (A249617) - and each integer partition > 0 to an infinite number of set partitions.

Furthermore each permutation and partition can be assigned a number that for simplicity's sake is called "blocks" in the diagram:
For permutations these are the cycles except fixed points (A055090), for set partitions the non-singleton blocks (A249615) and for integer partitions the non-one addends (A194548).

And of course they can be assigned the total number of elements in these "blocks": A055093, A249616 and a staircase like sequence that is too boring to be in the OEIS.

 A198380 cycle typeof the n-th permutation A055089 n-th permutationas triangle row A249618 set partitionof the n-th permutation A231428 n-th set partitioninterpreted as binary number A249617 integer partitionof the n-th set partition A194602 n-th integer partitioninterpreted as binary number A055090 number of cyclesin the n-th permutation A055093 number of elementsmoved by the n-th permutation A249615 number of non-singleton blocksin the n-th set partition A249616 number of non-singleton elementsin the n-th set partition A194548 number of non-one addendsin the n-th integer partition a(0)=0; p=A000041; n≥1: p(i−1)≤n

## Equalities

 pe2ip = sp2ip( pe2sp ) A198380 = A249617( A249618 ) pe2bl = sp2bl( pe2sp ) = ip2bl( sp2ip( pe2sp ) ) A055090 = A249615( A249618 ) = A194548( A249617( A249618 ) ) sp2bl = ip2bl( sp2ip ) A249615 = A194548( A249617 ) pe2el = sp2el( pe2sp ) = ip2el( sp2ip( pe2sp ) ) A055093 = A249616( A249618 ) = ip2el( A249617( A249618 ) ) sp2el = ip2el( sp2ip ) A249616 = ip2el( A249617 )

For simplicity's sake it is assumed that A231428 and A194548 have index 0 like all the other sequences, although at the moment they have index 1 in the OEIS.