login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
A105627
Column 1 of triangle
A105626
.
2
1, 6, 48, 480, 5736, 79584, 1256808, 22262640, 437315016, 9438589824, 222109617288, 5661445534800, 155427839133096, 4573268363775264, 143592923776842408, 4792636497324986160, 169456698405536983176
(
list
;
graph
;
refs
;
listen
;
history
;
text
;
internal format
)
OFFSET
0,2
COMMENTS
A105626
equals the cube of the matrix square-root of triangle
A105615
.
LINKS
Table of n, a(n) for n=0..16.
PROG
(PARI) {a(n)=local(R, M=matrix(n+2, n+2, m, j, if(m>=j, if(m==j, 1, if(m==j+1, -2*j, polcoeff(1/sum(i=0, m-j, (2*i)!/i!/2^i*x^i)+O(x^m), m-j)))))^-3); R=(M+M^0)/2; for(i=1, floor(2*log(n+2)), R=(R+M*R^(-1))/2); return(if(n<0, 0, R[n+2, 2]))}
CROSSREFS
Cf.
A105615
,
A105626
.
Sequence in context:
A261834
A226740
A244509
*
A051578
A052639
A248744
Adjacent sequences:
A105624
A105625
A105626
*
A105628
A105629
A105630
KEYWORD
nonn
AUTHOR
Paul D. Hanna
, Apr 16 2005
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 March 29 05:48 EDT 2024. Contains 371265 sequences. (Running on oeis4.)