|
| |
|
|
A124753
|
|
a(3n+k)=(k+1)*binomial(4n+k,n)/(3n+k+1), k=0,..2.
|
|
2
| |
|
|
1, 1, 1, 1, 2, 3, 4, 9, 15, 22, 52, 91, 140, 340, 612, 969, 2394, 4389, 7084, 17710, 32890, 53820, 135720, 254475, 420732, 1068012, 2017356, 3362260, 8579560, 16301164, 27343888, 70068713, 133767543, 225568798, 580034052
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,5
|
|
|
COMMENTS
| Row sums of Riordan array (1,x(1-x^3))^(-1). Also row sums of A124752. a(3n)=A002293(n), a(3n+1)=A069271(n), A(3n+2)=A006632(n).
|
|
|
FORMULA
| a(n)=((mod(n,3)+1)*C(4*floor(n/3)+mod(n,3),floor(n/3))/(3*floor(n/3)+1+mod(n,3))); - Paul Barry (pbarry(AT)wit.ie), Dec 14 2006
|
|
|
CROSSREFS
| Cf. A118968.
Sequence in context: A033076 A121431 A084080 * A049909 A096781 A192818
Adjacent sequences: A124750 A124751 A124752 * A124754 A124755 A124756
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Nov 06 2006
|
| |
|
|
