|
|
A301280
|
|
Nearest integer to variance of n-th row of Pascal's triangle.
|
|
4
|
|
|
0, 0, 0, 1, 5, 16, 56, 198, 699, 2490, 8943, 32355, 117800, 431316, 1587207, 5867244, 21777203, 81127591, 303240041, 1136914129, 4274441613, 16111746161, 60873695892, 230495640009, 874525192278, 3324270554675, 12658405644200, 48280298159610
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,5
|
|
LINKS
|
|
|
FORMULA
|
The variance is binomial(2*n,n)/n - 4^n/(n*(n+1)).
a(n) ~ 4^n/((sqrt(Pi)*n^(3/2)). (End)
|
|
EXAMPLE
|
The first few variances are 0, 0, 1/3, 4/3, 47/10, 244/15, 1186/21, 1384/7, 25147/36, 112028/45, 98374/11, 1067720/33, 1531401/13, 39249768/91, 166656772/105, 88008656/15, 2961699667/136, 12412521388/153, 51854046982/171, 108006842264/95, 448816369361/105, ...
|
|
MAPLE
|
M:=70;
m := n -> 2^n/(n+1);
v := n -> (1/n) * add((binomial(n, i) - m(n))^2, i=0..n );
# Alternative:
f:= n -> round((binomial(2*n, n)-4^n/(n+1))/n): f(0):=0:
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|