|
Search: id:A124383
|
|
|
| A124383 |
|
O.g.f.: A(x) = Sum_{n>=0} x^n*Product_{k=0..n} (1 + k*x)^2. |
|
+0
1
|
|
| 1, 1, 3, 8, 26, 91, 349, 1431, 6253, 28860, 140064, 711433, 3768601, 20754377, 118513699, 700096184, 4269686754, 26835429731, 173541095213, 1153074832175, 7861658903709, 54937031541660, 393050395468752, 2876341596372209
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
EXAMPLE
|
A(x) = 1 + x*(1+x)^2 + x^2*(1+x)^2*(1+2x)^2 + x^3*(1+x)^2*(1+2x)^2*(1+3x)^2 +...
|
|
PROGRAM
|
(PARI) a(n)=polcoeff(sum(k=0, n, x^k*prod(j=0, k, 1+j*x+x*O(x^n))^2), n)
|
|
CROSSREFS
|
Sequence in context: A000237 A081497 A028270 this_sequence A074506 A124528 A006870
Adjacent sequences: A124380 A124381 A124382 this_sequence A124384 A124385 A124386
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Paul D. Hanna (pauldhanna(AT)juno.com), Oct 28 2006
|
|
|
Search completed in 0.002 seconds
|
