[seqfan] Re: sums of signed squares

[rhhardin at att.net]

Terms for 1..56

0 0 0 0 0 0 2 2 0 0 2 10 0 0 86 114 0 0 478 860 0 0 5808 10838 0 0 55626 100426
0 0 696164 1298600 0 0 7826992 14574366 0 0 100061106 187392994 0 0 1223587084 2322159814
0 0 16019866270 30353305134 0 0 207366863690 395899408130 0 0 2773156759854 5301226883378


--
rhhardin at mindspring.com
rhhardin at att.net (either)
  
-------------- Original message ----------------------
From: Brendan McKay <bdm at cs.anu.edu.au>
>
> Another problem from the Mathematics help desk at Wikipedia:
> 
> How many ways to write 0 as a sum
>   +- 1^2 +- 2^2 +- 3^2 +- ... +- n^2 ?
> Here "+-" is "plus or minus".
> 
> Seems to be 0 for n <= 6, then starting at n=7:
>    2,2,0,0,2,10,0,0,86,114,...
> 
> Brendan.
> 
> 
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