This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
13^2 = 169 and 14 is the next smallest number whose square (in this case 196) contains the digits 1,6,9.
import Data.List ((\\))
a014563 n = a014563_list !! n
a014563_list = 1 : f 1 (drop 2 a000290_list) where
f x (q:qs) | null $ xs \\ (show q) = y : f y qs
| otherwise = f x qs
where y = a000196 q; xs = show (x * x)
-- Reinhard Zumkeller, Nov 22 2012
snd[n_]:=Module[{k=n+1},While[!AllTrue[Select[Transpose[{DigitCount[n^2],
DigitCount[k^2]}],#[[1]]>0&],#[[1]]<=#[[2]]&],k++];k]; NestList[ snd,1,40] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 21 2016 *)
import Data.List ((\\))
a066825 n = a066825_list !! (n-1)
a066825_list = 1 : f 1 (drop 2 a000290_list) where
f x (q:qs) | all (`elem` show q) xs = y : f y qs
| otherwise = f x qs
where y = a000196 q; xs = show (x * x)
-- Reinhard Zumkeller, Nov 22 2012
a(3) = 169; the smallest square obtained by inserting digits in it is 1369 hence a(4) = 1369.
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