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Search: id:A067225
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| A067225 |
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Numbers n such that n is a square and remains a square when its leading digit is increased by one. |
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+0
1
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| 576, 2025, 11025, 57600, 202500, 342225, 950625, 1102500, 3515625, 5760000, 9272025, 11390625, 20250000, 34222500, 95062500, 110250000, 196700625, 351562500, 576000000, 927202500, 1139062500, 2025000000, 3422250000
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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576 = 24^2 and 676 = 26^2, so 576 is a term of the sequence.
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MAPLE
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for n from 1 to 10^6 do if issqr(n^2+10^(length(n^2)-1)) then printf(`%d, `, n^2); fi:od:
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MATHEMATICA
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f[n_] := Block[{a = IntegerDigits[n]}, a[[1]] = a[[1]] + 1; FromDigits[a]]; Select[ Range[10^5], IntegerQ[ Sqrt[ f[ #^2]]] & ]^2
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CROSSREFS
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Sequence in context: A060678 A137484 A064254 this_sequence A036514 A079396 A013775
Adjacent sequences: A067222 A067223 A067224 this_sequence A067226 A067227 A067228
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KEYWORD
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base,nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Feb 20 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 21 2002
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