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A047899 a(1) = 7; for n > 0, a(n+1) = a(n) * sum of digits of a(n).

%I A047899 #16 Feb 17 2024 10:34:31
%S A047899 7,49,637,10192,132496,3312400,43061200,688979200,33759980800,
%T A047899 1755519001600,70220760064000,2387505842176000,138475338846208000,
%U A047899 9693273719234560000,736688802661826560000,64828614634240737280000
%N A047899 a(1) = 7; for n > 0, a(n+1) = a(n) * sum of digits of a(n).
%H A047899 Reinhard Zumkeller, <a href="/A047899/b047899.txt">Table of n, a(n) for n = 1..250</a>
%F A047899 a(n+1) = A057147(a(n)). - _Reinhard Zumkeller_, Mar 19 2014
%o A047899 (Haskell)
%o A047899 a047899 n = a047899_list !! (n-1)
%o A047899 a047899_list = iterate a057147 7  -- _Reinhard Zumkeller_, Mar 19 2014
%Y A047899 Cf. A047892 (start=2), A047912 (start=3), A047897 (start=5), A047898 (start=6), A047900 (start=8), A047901 (start=9), A047902 (start=11).
%K A047899 nonn,base,easy
%O A047899 1,1
%A A047899 Miklos SZABO (mike(AT)ludens.elte.hu)