|
| |
|
|
A073178
|
|
a(n) = n!^2 times coefficient of x^n in e^(x*(3-x)/2/(1-x))/(1-x)^(1/2).
|
|
1
| |
|
|
1, 2, 13, 180, 4266, 153180, 7725510, 519629040, 44880355800, 4835536256880, 635221698211800, 99872627051181600, 18507444606249152400, 3990439472567239692000, 990119486841576670378800
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
REFERENCES
| R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.65(b).
|
|
|
FORMULA
| e^(x*(3-x)/2/(1-x))/(1-x)^(1/2) = Sum_{n>=0} a(n)*x^n/n!^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 01 2006
|
|
|
PROG
| (PARI) a(n)=if(n<0, 0, n!^2*polcoeff(exp(x*(3-x)/2/(1-x)+x*O(x^n))/sqrt(1-x+x*O(x^n)), n))
|
|
|
CROSSREFS
| Cf. A049088.
Sequence in context: A119400 A183606 A137610 * A193192 A062156 A049512
Adjacent sequences: A073175 A073176 A073177 * A073179 A073180 A073181
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Michael Somos, Jul 19 2002
|
| |
|
|
