[seqfan] Re: Idea for a sequence

[israel at math.ubc.ca]

Those aren't the only ones.  For example,

1313125^2 = 1724297265625
2593125^2 = 6724297265625

4446875^2 = 19774697265625
8353125^2 = 69774697265625

4055515625^2 = 16447206984619140625
8151515625^2 = 66447206984619140625

Hmm, the sequence 80625, 890625, 724297265625, 9774697265625, 
6447206984619140625, ... doesn't seem to be in OEIS yet.

Cheers,
Robert


On Nov 25 2015, Hans Havermann wrote:

> I don't believe that there are further terms. If the only numbers that 
> are square when prepended by 1 or 6 are 80625 and 890625 followed by an 
> even number of zeros, none of these numbers are square when prepended by 
> 80625.
>
>
>> On Nov 24, 2015, at 11:55 PM, David Wilson <davidwwilson at comcast.net> 
>> wrote:
>> 
>> a(n) > 1 = smallest value such that a(i) concat a(n) is square for all 
>> i < n.
>> 
>> Starts
>> 
>> 1,6,80625
>> 
>> Are there any further elements?
>
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