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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A105631 Row sums of triangle A105629, which is the matrix logarithm of triangle A105623. 1
0, 1, 5, 27, 195, 1833, 21125, 286451, 4453859, 78031153, 1520668645, 32631020011, 764640901539, 19431070911513, 532315915981605, 15640217893829891, 490640673319698179, 16368499360721508833, 578693283962999831365 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

A105623 equals the matrix square-root of triangle A105615.

LINKS

Table of n, a(n) for n=0..18.

PROG

(PARI) {a(n)=local(L, M=matrix(n+1, n+1, 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)))))^-1); L=sum(i=1, #M, (-1)^(i-1)*(M-M^0)^i/i); return(if(n<0, 0, sum(k=0, n, L[n+1, k+1])/2))}

CROSSREFS

Cf. A105629, A105623, A105615.

Sequence in context: A240637 A023811 A126119 * A167019 A342904 A230563

Adjacent sequences:  A105628 A105629 A105630 * A105632 A105633 A105634

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 December 6 13:24 EST 2021. Contains 349563 sequences. (Running on oeis4.)