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A281822
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Least number k such that (k+n)^2 contains k as a substring.
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2
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1, 8, 6, 1, 4, 9, 62, 6, 1, 1, 1, 1, 1, 1, 2, 2, 2, 4, 1, 5, 1, 2, 9, 2, 4, 2, 92, 9, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 1, 2, 1, 2, 2, 1, 3, 1, 3, 3, 1, 2, 1, 4, 4, 2, 4, 4, 2, 4, 1, 5, 1, 1, 5, 2, 4, 2, 4, 2, 1, 5, 1, 6, 5, 2, 4, 8, 6
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OFFSET
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0,2
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LINKS
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EXAMPLE
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a(1) = 8 because (8 + 1)^2 = 9^2 = 81 contains 8 as a substring and it is the least number with this property.
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MAPLE
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with(numtheory): P:= proc(q) local a, b, d, j, k, n, ok;
for n from 0 to q do for k from 1 to q do a:=ilog10(k)+1; b:=(n+k)^2; d:=ilog10((k+n)^2)-ilog10(k)+1;
ok:=0; for j from 1 to d do if k=(b mod 10^a) then ok:=1; break; else b:=trunc(b/10); fi; od;
if ok=1 then print(k); break; fi; od; od; end: P(10^6);
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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Entries, Maple code and b-file corrected at the suggestion of Harvey P. Dale, Feb 28 2017.
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STATUS
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approved
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