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A250435
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Numbers whose squares remain squares when prepended with 9 and appended with 25 in base 10.
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3
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30, 12834, 18141477989940702510, 48095105831852088000, 5437693915503684117819750, 5784962279163039331595016, 864479870564593025822726220, 24351951618610295127241673897127630, 25652594148194488759500411647073225254466
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OFFSET
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1,1
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LINKS
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EXAMPLE
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30^2 = 900, 990025 = 995^2.
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MAPLE
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F:= proc(d) local m, D, P;
m:= 9*10^d+25;
D:= numtheory:-divisors(m);
P:= map(t -> (m/t - t)/20, select(t -> t^2 < m and (m/t - t) mod 20 = 0, D));
op(select(t -> 10^(d-3) <= t^2 and t^2 < 10^(d-2), P));
end proc:
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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STATUS
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approved
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