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A047898 a(1) = 6; for n > 0, a(n+1) = a(n) * (sum of digits of a(n)).

%I A047898 #36 Mar 07 2025 16:13:14
%S A047898 6,36,324,2916,52488,1417176,38263752,1377495072,61987278240,
%T A047898 3347313024960,150629086123200,6778308875544000,488038239039168000,
%U A047898 35138753210820096000,2213741452281666048000,159389384564279955456000
%N A047898 a(1) = 6; for n > 0, a(n+1) = a(n) * (sum of digits of a(n)).
%H A047898 Reinhard Zumkeller, <a href="/A047898/b047898.txt">Table of n, a(n) for n = 1..250</a>
%F A047898 a(n+1) = A057147(a(n)). - _Reinhard Zumkeller_, Mar 19 2014
%t A047898 Nest[Append[#, # Total@ IntegerDigits@ # &@ Last[#]] &, {6}, 15] (* _Michael De Vlieger_, Jul 08 2019 *)
%o A047898 (Haskell)
%o A047898 a047898 n = a047898_list !! (n-1)
%o A047898 a047898_list = iterate a057147 6  -- _Reinhard Zumkeller_, Mar 19 2014
%o A047898 (Python)
%o A047898 A047898_list, l = [6], 6
%o A047898 for _ in range(10**2):
%o A047898     l *= sum(int(d) for d in str(l))
%o A047898     A047898_list.append(l) # _Chai Wah Wu_, Jan 04 2015
%Y A047898 Cf. A047892 (start=2), A047912 (start=3), A047897 (start=5), A047899 (start=7), A047900 (start=8), A047901 (start=9), A047902 (start=11).
%K A047898 easy,nonn,base
%O A047898 1,1
%A A047898 Miklos SZABO (mike(AT)ludens.elte.hu)