Question 1120996
Is there formula {{{a[n]=2n*a[n-1]}}}
{{{a[1]=-3}}}
{{{n=2}}}, then {{{a[2]=2*2*a[1]=4*(-3)=-12}}}
{{{n=3}}}, then {{{a[3]=2*3*a[2]=6*(-12)=-72}}}

{{{n=4}}}, then {{{a[4]=2*4*a[3]=8*(-72)=-576}}}
Answer: -3, -12, -72, -576