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A230543
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Numbers n that form a Pythagorean quadruple with n', n'' and sqrt(n^2 + n'^2 + n''^2), where n' and n'' are the first and the second arithmetic derivative of n.
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5
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512, 1203, 3456, 6336, 23328, 42768, 157464, 249753, 288684, 400000, 722718, 1062882, 1948617, 2700000, 4950000, 18225000, 33412500, 105413504, 123018750, 225534375, 312500000, 408918816
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OFFSET
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1,1
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COMMENTS
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Tested up to n = 4.09*10^8.
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LINKS
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EXAMPLE
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If n = 6336 then n' = 23808, n'' = 103936 and sqrt(n^2 + n'^2 + n''^2) = 106816.
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MAPLE
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with(numtheory): P:= proc(q) local a1, a2, n, p;
for n from 2 to q do a1:=n*add(op(2, p)/op(1, p), p=ifactors(n)[2]);
a2:=a1*add(op(2, p)/op(1, p), p=ifactors(a1)[2]);
if type(sqrt(n^2+a1^2+a2^2), integer) then print(n);
fi; od; end: P(10^10);
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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