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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A105630 Column 0 of triangle A105629, which is the matrix logarithm of triangle A105623. 1
 0, 1, 3, 17, 135, 1353, 16251, 226857, 3605775, 64288209, 1270969971, 27603549057, 653517822615, 16755529944729, 462601460800491, 13685474246611737, 431948067953729055, 14489465807596684449, 514794897939436455651 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS A105623 equals the matrix square-root of triangle A105615. LINKS 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, L[n+1, 1]/2))} CROSSREFS Cf. A105629, A105623, A105615. Sequence in context: A093986 A192459 A055214 * A199138 A006290 A060003 Adjacent sequences:  A105627 A105628 A105629 * A105631 A105632 A105633 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.

Last modified September 24 03:21 EDT 2020. Contains 337315 sequences. (Running on oeis4.)