|
|
A115254
|
|
Diagonal sums of correlation triangle for Catalan numbers.
|
|
1
|
|
|
1, 1, 3, 7, 19, 52, 162, 505, 1666, 5576, 19135, 66494, 234316, 833620, 2992817, 10822802, 39395434, 144207387, 530534468, 1960521470, 7273963575, 27085625086, 101188629692, 379160330195, 1424634014730, 5366319233160
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
Diagonal sums of number triangle A115253.
|
|
LINKS
|
|
|
FORMULA
|
G.f.: c(x)c(x^2)/(1-x^3) where c(x) is the g.f. of A000108; a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, [j<=k]*C(k-j)[j<=n-2k]*C(n-2k-j)}}.
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|