Bernoulli( n )
Bernoulli returns the n-th Bernoulli number B_n, which is defined
by B_0 = 1 and B_n = -sum_{k=0}^{n-1}{{n+1 choose k} B_k}/(n+1).
B_n/n! is the coefficient of x^n in the power series of x/{e^x-1}. Except for B_1=-1/2 the Bernoulli numbers for odd indices m are zero.
gap> Bernoulli( 4 );
-1/30
gap> Bernoulli( 10 );
5/66
gap> Bernoulli( 12 );
-691/2730 # there is no simple pattern in Bernoulli numbers
gap> Bernoulli( 50 );
495057205241079648212477525/66 # and they grow fairly fast
GAP 3.4.4