login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A166886 Column 2 of triangle A166884. 3
1, 2, 9, 62, 593, 7266, 108720, 1922166, 39212154, 906623004, 23429034168, 669203550906, 20935080981744, 711872134399868, 26142553369667634, 1031146768716808794, 43475757877044427198, 1951261759908828697902 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Triangle A166884 transforms diagonals in the triangle A166880 of coefficients in the successive iterations of x+x^2+x^3.
LINKS
PROG
(PARI) {a(n)=local(F=x, M, N, P, m=n+1); M=matrix(m+2, m+2, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, x+x^2+x^3+x*O(x^(m+2)))); polcoeff(F, c)); N=matrix(m+1, m+1, r, c, M[r, c]); P=matrix(m+1, m+1, r, c, M[r+1, c]); (P~*N~^-1)[n+2, 2]}
CROSSREFS
Sequence in context: A052820 A213528 A100262 * A212413 A003577 A085928
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 21 2009
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 08:08 EDT 2024. Contains 371265 sequences. (Running on oeis4.)