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A018834 Numbers k such that the decimal expansion of k^2 contains k as a substring. 17
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
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.
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
(Python)
from itertools import count, islice
def A018834_gen(startvalue=0): # generator of terms >= startvalue
return filter(lambda n:str(n) in str(n**2), count(max(startvalue, 0)))
A018834_list = list(islice(A018834_gen(), 20)) # Chai Wah Wu, Apr 04 2023
CROSSREFS
Cf. A000290. Supersequence of A029943.
Sequence in context: A035282 A075156 A075904 * A029943 A356760 A063630
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)