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A047901 a(1) = 9; a(n+1) = a(n) * sum of decimal digits of a(n). 9

%I

%S 9,81,729,13122,118098,3188646,114791256,4132485216,148769467776,

%T 10711401679872,578415690713088,41645929731342336,2998506940656648192,

%U 296852187125008171008,24045027157125661851648,2164052444141309566648320

%N a(1) = 9; a(n+1) = a(n) * sum of decimal digits of a(n).

%H Reinhard Zumkeller, <a href="/A047901/b047901.txt">Table of n, a(n) for n = 1..250</a>

%F a(n+1) = A057147(a(n)). - _Reinhard Zumkeller_, Mar 19 2014

%o (Haskell)

%o a047901 n = a047901_list !! (n-1)

%o a047901_list = iterate a057147 9 -- _Reinhard Zumkeller_, Mar 19 2014

%o (Python)

%o A047901_list, l = [9], 9

%o for _ in range(10**2):

%o ....l *= sum(int(d) for d in str(l))

%o ....A047901_list.append(l) # _Chai Wah Wu_, Jan 04 2015

%Y Cf. A047892 (start=2), A047912 (start=3), A047897 (start=5), A047898 (start=6), A047899 (start=7), A047900 (start=8), A047902 (start=11).

%K easy,nonn,base

%O 1,1

%A Miklos SZABO (mike(AT)ludens.elte.hu)

%E Edited by _Charles R Greathouse IV_, Aug 02 2010

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Last modified June 18 18:17 EDT 2021. Contains 345120 sequences. (Running on oeis4.)