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A277441
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Least number k such that k^2 can be obtained from k by inserting n internal (but not necessarily contiguous) digits.
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1
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0, 10, 95, 950, 9500, 89476, 894760, 8946105, 89448001, 894438005, 8944300005, 89442827780, 894427300005, 8944273000005, 89442720000005, 894427196000005, 8944271912400005, 89442719120000005, 894427191000000005, 8944271910000000005, 89442719100000000005, 894427191000000000005
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OFFSET
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0,2
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COMMENTS
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A subsequence of A046851.
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LINKS
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Table of n, a(n) for n=0..21.
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EXAMPLE
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a(2) = 95 as 95 is the least number that needs two internal digits inserted to become its square, i.e., 95 squared is 9(02)5.
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MAPLE
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P:=proc(q) local a, b, d, j, k, n, ok, t; t:=1; print(0);
for n from 1 to q do for k from t to q do if ilog10(k^2)=ilog10(k)+n then
if (k^2 mod 10)=(k mod 10) and trunc(k^2/10^(ilog10(k^2)))=trunc(k/10^(ilog10(k))) then
a:=convert(k, base, 10); b:=convert(k^2, base, 10); ok:=1; d:=1;
for j from 2 to nops(a)-1 do while d<nops(b)-1 do d:=d+1; if a[j]=b[d] then break; fi; od;
if d=nops(b)-1 and j<=nops(a)-1 then ok:=0; break; fi; od;
if ok=1 then t:=k; print(k); break; fi; fi; fi; od; od; end: P(10^15); # Paolo P. Lava, Oct 20 2016
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CROSSREFS
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Cf. A046851, A277442.
Sequence in context: A163738 A190987 A233738 * A307021 A197083 A197086
Adjacent sequences: A277438 A277439 A277440 * A277442 A277443 A277444
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KEYWORD
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nonn,base
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AUTHOR
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Ivan N. Ianakiev, Oct 15 2016
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EXTENSIONS
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More terms from Paolo P. Lava, Oct 20 2016
a(13)-a(21) from Giovanni Resta, Jul 06 2019
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STATUS
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approved
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