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A291629
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Numbers k such that 4 is the smallest decimal digit of k^2.
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7
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2, 7, 8, 22, 28, 67, 74, 88, 92, 93, 212, 214, 216, 234, 238, 242, 258, 262, 293, 308, 667, 676, 678, 683, 684, 692, 707, 738, 758, 772, 817, 822, 828, 863, 864, 866, 886, 888, 892, 893, 926, 938, 972, 974, 978, 2113, 2114, 2116, 2133, 2137, 2158, 2163, 2167
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OFFSET
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1,1
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COMMENTS
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First digit can't be 1, 4 or 5; last digit can't be 0, 1 or 9. - Robert Israel, Mar 25 2020
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LINKS
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EXAMPLE
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28 is in the sequence because 28^2 = 784, the smallest decimal digit of which is 4.
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MAPLE
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filter:= n -> min(convert(n^2, base, 10))=4:
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MATHEMATICA
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Select[Range[2500], Min[IntegerDigits[#^2]]==4&] (* Harvey P. Dale, Aug 03 2019 *)
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PROG
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(PARI) select(k->vecmin(digits(k^2))==4, vector(3000, k, k))
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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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