Final Proof of the Identity and of the Second Order Recurrence
Let
be any solution of the second order recurrence which has been obtained for the left-hand side:
> rec[left];
Thus:
> h(n+2)=collect(solve(",h(n+2)),h,normal);
> subs(n=n+1,");
and
> subs(n=n+1,");
Then,
also solves the recurrence for the right-hand side:
> collect(subs(","",""",rec[right]),h,normal);
At this point, we have proved that both sides of the equation satisfy the same recurrence of order 4. To prove the announced equality, we simply need to check 4 initial conditions, since the leading coefficient of the recurrence of order 4,
> coeff(rec[right],h(n+3));
never vanishes for non-negative
. Now the proof of the identity
>
simplify follows from
> eval(subs(n=0,Sum=add,eq));
> eval(subs(n=1,Sum=add,eq));
> eval(subs(n=2,Sum=add,eq));
> eval(subs(n=3,Sum=add,eq));
Therefore, the Apéry numbers also satisfy the announced second order recurrence.