login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 23 03:02 EST 2021. Contains 340384 sequences. (Running on oeis4.)