Write down the first five terms of the sequence an=(n+1)!7n2+2n+6\displaystyle {a}_{{n}}=\frac{{{\left({n}+{1}\right)}!}}{{{7}{n}^{{2}}+{2}{n}+{6}}}

a1 =  
a2 =  
a3 =  
a4 =  
a5 =