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A344110 Triangle read by rows: T(n,k) = 2^(n*k), n >= 0, 0 <= k <= n. 8
1, 1, 2, 1, 4, 16, 1, 8, 64, 512, 1, 16, 256, 4096, 65536, 1, 32, 1024, 32768, 1048576, 33554432, 1, 64, 4096, 262144, 16777216, 1073741824, 68719476736, 1, 128, 16384, 2097152, 268435456, 34359738368, 4398046511104, 562949953421312 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
T(n, k) is the number of relations from an n-element set into a k-element set, n >= 0, 0 <= k <= n.
T(n,k) is the size of the right principal ideal generated by A where A is an n X n matrix over GF(2) having rank k. The right principal ideal of A contains precisely the matrices whose image is contained in the image of A. - Geoffrey Critzer, Sep 25 2022
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..1325 (rows n = 0..50, flattened)
Mohammad K. Azarian, Remarks and Conjectures Regarding Combinatorics of Discrete Partial Functions, Int'l Math. Forum (2022) Vol. 17, No. 3, 129-141.
FORMULA
T(n,k) = 2^(n*k).
T(n,k) = Sum_{j=0..k} A288853(n,j)*A022166(n,j). - Geoffrey Critzer, Jan 02 2023
EXAMPLE
T(3,3) = number of relations from a 3-element set into a 3-element set=2^(3*3)=512.
Triangle begins:
1
1 2
1 4 16
1 8 64 512
1 16 256 4096 65536
1 32 1024 32768 1048576 33554432
...
MATHEMATICA
Table[2^(n*k), {n, 0, 10}, {k, 0, n}]
CROSSREFS
Sequence in context: A162977 A032174 A212267 * A346793 A087801 A238454
KEYWORD
easy,nonn,tabl
AUTHOR
Mohammad K. Azarian, May 10 2021
STATUS
approved

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Last modified August 21 12:48 EDT 2024. Contains 375353 sequences. (Running on oeis4.)