|
|
A107031
|
|
Diagonal sums of number triangle A107030.
|
|
1
|
|
|
1, 2, 3, 4, 7, 12, 25, 56, 145, 422, 1389, 5072, 20283, 87996, 412663, 2087868, 11361831, 66155642, 409567833, 2680486870, 18465061963, 133504614880, 1011121118741, 8008145020804, 66201411633209, 570006877641976
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
a(n)=sum{k=0..floor(n/2), (k-1)*C(k(n-2k), n-2k)-(k-2)*sum{j=0..n-k, C(k(n-2k), j)}}
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|