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A068617
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Starting from a(1)=8, each subsequent term is the minimal square obtained by inserting at least one digit in the previous term.
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0
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8, 81, 841, 38416, 3841600, 384160000, 38416000000, 3841600000000, 384160000000000, 38416000000000000, 3841600000000000000, 384160000000000000000, 38416000000000000000000
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OFFSET
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1,1
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COMMENTS
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The growing square sequence for 1 and 6, 2 and 5, 4 and 9 in pairs are the same.
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LINKS
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FORMULA
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For n>=4, a(n) = 38416*100^(n-4).
a(n) = 100*a(n-1) for n > 4.
G.f.: x*(45684*x^3 + 7259*x^2 + 719*x - 8)/(100*x - 1). (End)
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EXAMPLE
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a(2)=81 hence a(3) = 841 the smallest square formed from 81.
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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