[seqfan] Re: A045655

David Wilson davidwwilson at comcast.net
Sun Jan 1 23:40:30 CET 2012

On 1/1/2012 3:52 PM, Olivier Gerard wrote:
> Hello,
> The comment by Geoffrey is indeed correct but his various programs were
> inefficient or relying on obsolete librairies not loaded (i.e.
> Combinatorica).
> I have replaced it by another version and added a few comments.
> There should be a formula in the form of a sum of squares giving the
> general term of the sequence instead of brute force enumeration.
> Olivier

I think you are looking for

A045655(n) = sum(d|n, n*A027375(n)) = sum(d|n, n^2*A001037(n))


sum(d|n, A027375(n)) = 2^n.

sum(d|n, A001037(n)) = A000031(n).

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