|
|
A254744
|
|
a(n) = 2^n * Sum_{k=1 .. n-1} a(k) * a(n-1-k) with a(0) = 1.
|
|
2
|
|
|
1, 2, 16, 288, 10240, 700416, 92864512, 24184487936, 12484798840832, 12835745584644096, 26339606633209921536, 107993030830149951553536, 885112171099428768672907264, 14505223494706550858367937544192, 475365227058478388903633481696804864
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
In Blieberger and Kirschenhofer 2014 denoted by r_n on page 106 equation (5).
|
|
LINKS
|
|
|
FORMULA
|
a(n) ~ 2^((n^2 + 3*n)/2) * c where c = 0.7153374336... .
|
|
PROG
|
(PARI) {a(n) = if( n<1, n==0, 2^n * sum(k=0, n-1, a(k) * a(n-1-k)))};
(Haskell)
a254744 n = a254744_list !! n
a254744_list = 1 : f 2 [1] where
f x ys = y : f (x * 2) (y : ys) where
y = x * (sum $ zipWith (*) ys $ reverse ys)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|