[seqfan] Re: A006451 = n such that n*(n+1)/2+1 is square?
Joerg Arndt
arndt at jjj.de
Sat Oct 10 11:39:16 CEST 2009
* Joerg Arndt <arndt at jjj.de> [Oct 10. 2009 20:11]:
> [...]
Please ignore the following part of the previous message,
I did not think enough before sending.
<please_ignore>
> Some Diophantinista may want to enter seq
> k such that n*(n+1)+k can be square.
> (might be unworthy if trivial for some reason).
> Quick & dirty:
> ? for(k=0,20,q=0;for(n=1,10000,t=n*(n+1)/2+k;if(issquare(t),q=1;break())); if(q, print1(k,", ")))
> 0, 1, 3, 4, 6, 8, 9, 10, 13, 15, 16, 19,
> seq. not in OEIS, neither complement,
> neither for negative k.
</please_ignore>
cheers, jj
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