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A277946
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Squares whose largest decimal digit is 2.
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13
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121, 10201, 12100, 22201, 1002001, 1020100, 1022121, 1210000, 1212201, 2220100, 100020001, 100200100, 100220121, 102010000, 102212100, 121000000, 121022001, 121220100, 210221001, 222010000, 10000200001, 10002000100, 10002200121, 10020010000, 10020210201
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OFFSET
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1,1
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COMMENTS
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If n is a term, then so is 100*n.
The first term with an even number of digits is a(36) = 100021020121.
The first term with an even number of digits that is not of the form a(36)*100^k has at least 24 digits.
(End)
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LINKS
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FORMULA
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MAPLE
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res:= NULL: B:= [1, 2]:
for m from 1 to 10 do
for q in B do
for x from ceil(sqrt(10^m*q)) to floor(sqrt(10^m*q + 2/9*(10^m-1))) do
if max(convert(x^2, base, 10)) = 2 then res:= res, x^2 fi
od od:
for q in B do
for x from ceil(sqrt(10^(m+1)*q)) to floor(sqrt(10^(m+1)*q + 2/9*(10^(m+1)-1))) do
if max(convert(x^2, base, 10)) = 2 then res:= res, x^2 fi
od od:
if m < 10 then B:= map(t -> (10*t, 10*t+1, 10*t+2), B) fi;
od:
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MATHEMATICA
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fQ[n_] := Union[ IntegerDigits[ n^2]][[-1]] == 2; Select[ Range@100500, fQ]^2 (* Robert G. Wilson v, Nov 06 2016 *)
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PROG
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(PARI) L=List(); for(n=1, 10000, if(vecmax(digits(n^2))==2, listput(L, n^2))); Vec(L)
(Magma) [n^2: n in [1..1000000] | Maximum(Intseq(n^2)) eq 2]; // Vincenzo Librandi, Nov 06 2016
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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