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%I #10 Jan 19 2023 01:41:52
%S 3,19,33,91,139,193,319,333,391,913,931,1199,1339,1393,1919,1933,1991,
%T 3139,3193,3319,3333,3391,3913,3931,9119,9133,9191,9313,9331,9911,
%U 11399,11939,11993,13199,13339,13393,13919,13933,13991,19139,19193
%N Geometric mean of the digits = 3. In other words, the product of the digits is = 3^k where k is the number of digits.
%H Reinhard Zumkeller, <a href="/A061427/b061427.txt">Table of n, a(n) for n = 1..10000</a>
%e 319 is a term as the geometric mean of digits is (3*1*9) = 27 = 3^3.
%t Select[Range[20000],GeometricMean[IntegerDigits[#]]==3&] (* _Harvey P. Dale_, Dec 11 2011 *)
%o (Haskell)
%o a061427 n = a061427_list !! (n-1)
%o a061427_list = g [1] where
%o g ds = if product ds == 3 ^ length ds
%o then foldr (\d v -> 10 * v + d) 0 ds : g (s ds) else g (s ds)
%o s [] = [1]; s (9:ds) = 1 : s ds; s (d:ds) = 3*d : ds
%o -- _Reinhard Zumkeller_, Jan 13 2014
%Y Cf. A061426-A061430.
%Y Cf. A174813.
%K nonn,base,easy
%O 1,1
%A _Amarnath Murthy_, May 03 2001
%E More terms from Larry Reeves (larryr(AT)acm.org), May 16 2001