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A180259
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Squares which are the sum of consecutive squares starting with 25^2.
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3
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OFFSET
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1,1
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COMMENTS
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That is, terms are squares of the form sum_{i=25..m} i^2 = (m-24) *(2*m^2+51*m+1225) / 6 for some m. Known solutions refer to m = 25, 48, 50, 73, 578, 624, 3625 and 21624, and no further in the range m <= 70000000.
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LINKS
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EXAMPLE
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38025 is in the sequence because 38025 = 195^2 = 25^2 + 26^2 + ... + 50^2.
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MATHEMATICA
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Select[Accumulate[Range[25, 22000]^2], IntegerQ[Sqrt[#]] &] (* Harvey P. Dale, Aug 10 2023 *)
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PROG
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(PARI) for(n=26, 9999999, t=n*(n+1)*(2*n+1)/6-4900; if(issquare(t), print1(t, ", ")))
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CROSSREFS
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KEYWORD
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nonn,fini,full
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AUTHOR
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STATUS
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approved
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