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!)
A141761 Column 0 of triangle A141760. 8
1, 1, 1, 2, 6, 26, 154, 1188, 11474, 134432, 1863168, 29936846, 548625820, 11315025894, 259733293774, 6574304470320, 182050022755386, 5477819548007438, 178054691097463354, 6220193033111607018 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Also equals column 1 (shifted) of triangle A141760.

LINKS

Table of n, a(n) for n=0..19.

FORMULA

G.f.: 1/(1-x) = Sum_{n>=0} a(n) * x^n/(1+x)^{n*(n-1)/2}.

a(n) = 1 - Sum_{j=0..n-1} a(j) * (-1)^(n-j) * C(j(j-1)/2 + n-j-1, n-j) for n>0, with a(0)=1.

PROG

(PARI) {a(n)=if(n==0, 1, 1 - sum(j=0, n-1, a(j)*(-1)^(n-j)*binomial(j*(j-1)/2+n-j-1, n-j)))}

CROSSREFS

Cf. A141760, A141762, A141763, A141764.

Sequence in context: A032271 A205502 A107104 * A242574 A123306 A218691

Adjacent sequences:  A141758 A141759 A141760 * A141762 A141763 A141764

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jul 18 2008

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 February 17 23:35 EST 2020. Contains 332006 sequences. (Running on oeis4.)