[seqfan] Re: A001924

[Heinz, Alois]

Paolo's formula is correct.

Notice that it can be modified:  a(n) = Sum_{k=1..ceil(n/2)} C(n-k+2,k+1)

Alois

Am 28.12.2011 07:53, schrieb Ed Jeffery:
> Seqfans,
>
> A001924={0,1,3,7,14,26,...}. I am working on a formula for the nonzero
> terms of this sequence based on binomial coefficients only. But Paolo Lava
> has a formula already which doesn't seem to work properly: it is
>
> a(n)=Sum_{k=1..n} {C(n-k+2,k+1)}, with n>=0,
>
> as written by Paolo Lava. I assume that C(m,j) is a binomial coefficient.
> Is there something wrong with this formula and could someone else please
> check it, or am I having problems with Mathcad again (as usual)?