[seqfan] Re: a(n) divides the sum of the first a(n) terms of S

franktaw at netscape.net franktaw at netscape.net
Thu May 20 12:00:47 CEST 2010


However, if we take n divides the sum of the first n terms of S, with 
the weaker restriction that no term can have occurred before, we get 
the very beautiful http://www.research.att.com/~njas/sequences/A019444.

(I just submitted a formula for this:

Let s(n) = sum(k=1,n,a(k))/n = A019446(n). Then if s(n-1) does not 
occur in a(1),...,a(n-1), a(n) = s(n) = s(n-1); otherwise, a(n) = 
s(n-1) + n and s(n) = s(n-1) + 1.

and a corresponding PARI program.)

Franklin T. Adams-Watters

-----Original Message-----
From: franktaw at netscape.net

...

Of course n divides the sum of the first n terms of S is just the odd
numbers.

Franklin T. Adams-Watters




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