[seqfan] Re: Possible error in A190660

Jeremy Gardiner jeremy.gardiner at btinternet.com
Sun Aug 11 08:56:29 CEST 2013


Wouter,

Yes - thanks for verifying A190660 appears to be correct.
I've added a comment to A190660 'essentially first differences of A057048'.

Jeremy

On 10/8/13 16:41, "Wouter Meeussen" <wouter.meeussen at telenet.be> wrote:

> interval 
> ]1/2 , 1] :  1  :  t(1) = 1
> ]1 , 2]   :  0
> ]2 , 4]   :  1  :  t(2) = 2
> ]4 , 8]   :  1  :  t(3) = 6
> ]8 , 16]     2  :  t(4) = 10 ; t(5) = 15
> etc
> 
> no?
> 
> Wouter.
> 
> -----Original Message-----
> From: Jeremy Gardiner
> Sent: Saturday, August 10, 2013 4:12 PM
> To: Sequence Fanatics Discussion list
> Subject: [seqfan] Possible error in A190660
> 
> A190660 Number of triangular numbers T(k) between powers of 2, 2^(n-1) <
> T(k) <= 2^n
> 1, 0, 1, 1, 2, 2, 3, 5, 7, 9, 13, 19, 27, 37, 53, 75, 106, 150, ...
> 
> I calculate:
> 1, 0, 1, 1, 1, 2, 2, 3, 5, 7, 9, 13, 19, 27, 37, 53, 75, 106, 150, ...
> 
> Being first differences of A(n) = round(sqrt(2)^n), n = 0,1,...
> 
> A(n) = 1, 1, 2, 3, 4, 6, 8, 11, 16, 23, 32, 45, 64, 91, 128, 181
> 
> Cf. A057048
> 
> - Please can someone verify?





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