A066825 - OEIS

%I #11 Jul 13 2013 12:02:42

%S 1,4,13,14,31,36,54,96,113,311,487,854,1036,1277,1646,3214,3267,3723,

%T 4047,4554,4896,5376,10136,13147,13268,16549,20513,21877,25279,26152,

%U 27209,28582,31723,32043,32286,33144,35172,35337,35757,35853

%N a(1) = 1; set of digits of a(n)^2 is a subset of the set of digits of a(n+1)^2.

%C Probably infinite and dense over Z+.

%H Reinhard Zumkeller, <a href="/A066825/b066825.txt">Table of n, a(n) for n = 1..10000</a>

%o (Haskell)

%o import Data.List ((\\))

%o a066825 n = a066825_list !! (n-1)

%o a066825_list = 1 : f 1 (drop 2 a000290_list) where

%o    f x (q:qs) | all (`elem` show q) xs = y : f y qs

%o               | otherwise              = f x qs

%o               where y = a000196 q; xs = show (x * x)

%o -- _Reinhard Zumkeller_, Nov 22 2012

%Y Cf. A014563, A067633, A067634, A067635.

%Y Cf. A000290, A000196.

%K nonn,base

%O 1,2

%A _David W. Wilson_, Feb 05 2002