OFFSET
1,4
COMMENTS
LINKS
W. Lang, First 9 rows.
FORMULA
a(n, m)= binomial(2*n, 2*m+1)/(2*b(n)), n>=m+1>=1, else 0, with b(n) := GCD(seq(binomial(2*n, 2*m+1)/2, m=0..n-1)), where GCD denotes the greatest common divisor of a set of numbers (here one half of the odd numbered entries in the even numbered rows of Pascal's triangle). It suffices to consider m=0..floor((n-1)/2) due to symmetry.
EXAMPLE
CROSSREFS
KEYWORD
AUTHOR
Wolfdieter Lang, Jan 23 2004
STATUS
approved