login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A038015
Number of pointed (distinguished element) idempotent groupoids.
3
1, 4, 378, 2798336, 3973658465625, 1842282678468471349824, 433296503176904197061300041939288, 74235003800935257803650942510752495927455127552
(
list
;
graph
;
refs
;
listen
;
history
;
text
;
internal format
)
OFFSET
1,2
LINKS
Table of n, a(n) for n=1..8.
Index entries for sequences related to groupoids
FORMULA
Here fixF[n] = n(1)*Product_{i, j >= 1}(Sum_{d|[i, j]}(d*n(d))^((i, j)*n(i)*n(j)-(i=j)n(i))).
CROSSREFS
Cf.
A001329
,
A030247
.
Sequence in context:
A154682
A292195
A154569
*
A279525
A003753
A193130
Adjacent sequences:
A038012
A038013
A038014
*
A038016
A038017
A038018
KEYWORD
nonn
AUTHOR
Christian G. Bower
, May 15 1998
STATUS
approved
Lookup
|
Welcome
|
Wiki
|
Register
|
Music
|
Plot 2
|
Demos
|
Index
|
Browse
|
More
|
WebCam
Contribute new seq. or comment
|
Format
|
Style Sheet
|
Transforms
|
Superseeker
|
Recents
The OEIS Community
| Maintained by
The OEIS Foundation Inc.
License Agreements, Terms of Use, Privacy Policy.
.
Last modified April 23 15:20 EDT 2024. Contains 371916 sequences. (Running on oeis4.)