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A018834
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Numbers k such that decimal expansion of k^2 contains k as a substring.
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15
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0, 1, 5, 6, 10, 25, 50, 60, 76, 100, 250, 376, 500, 600, 625, 760, 1000, 2500, 3760, 3792, 5000, 6000, 6250, 7600, 9376, 10000, 14651, 25000, 37600, 50000, 60000, 62500, 76000, 90625, 93760, 100000, 109376, 250000, 376000, 495475, 500000, 505025
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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LINKS
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David W. Wilson and Giovanni Resta, Table of n, a(n) for n = 1..200 (first 126 terms from David W. Wilson)
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EXAMPLE
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25^2 = 625 which contains 25.
3792^2 = 14_3792_64, 14651^2 = 2_14651_801.
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MAPLE
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select(n->searchtext(convert(n, string), convert(n^2, string))>0, [$0..10^5]); # Paolo P. Lava, Apr 18 2018
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MATHEMATICA
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Select[Range[510000], MemberQ[FromDigits /@ Partition[IntegerDigits[#^2], IntegerLength[#], 1], #] &] (* Jayanta Basu, Jun 29 2013 *)
Select[Range[0, 510000], StringPosition[ToString[#^2], ToString[#]]!={}&] (* Ivan N. Ianakiev, Oct 02 2016 *)
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PROG
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(Haskell)
import Data.List (isInfixOf)
a018834 n = a018834_list !! (n-1)
a018834_list = filter (\x -> show x `isInfixOf` show (x^2)) [0..]
-- Reinhard Zumkeller, Jul 27 2011
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CROSSREFS
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Cf. A029942, A003226, A046831, A046851, A045953.
Cf. A000290. Supersequence of A029943.
Sequence in context: A035282 A075156 A075904 * A029943 A063630 A342127
Adjacent sequences: A018831 A018832 A018833 * A018835 A018836 A018837
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KEYWORD
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nonn,base
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AUTHOR
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David W. Wilson
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STATUS
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approved
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