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A018834 Numbers k such that decimal expansion of k^2 contains k as a substring. 15
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)
OFFSET

1,3

LINKS

David W. Wilson and Giovanni Resta, Table of n, a(n) for n = 1..200 (first 126 terms from David W. Wilson)

EXAMPLE

25^2 = 625 which contains 25.

3792^2 = 14_3792_64, 14651^2 = 2_14651_801.

MAPLE

select(n->searchtext(convert(n, string), convert(n^2, string))>0, [$0..10^5]); # Paolo P. Lava, Apr 18 2018

MATHEMATICA

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 *)

PROG

(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

CROSSREFS

Cf. A029942, A003226, A046831, A046851, A045953.

Cf. A000290. Supersequence of A029943.

Sequence in context: A035282 A075156 A075904 * A029943 A063630 A119102

Adjacent sequences:  A018831 A018832 A018833 * A018835 A018836 A018837

KEYWORD

nonn,base

AUTHOR

David W. Wilson

STATUS

approved

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Last modified September 25 15:05 EDT 2018. Contains 315391 sequences. (Running on oeis4.)