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

6, 36, 324, 2916, 52488, 1417176, 38263752, 1377495072, 61987278240, 3347313024960, 150629086123200, 6778308875544000, 488038239039168000, 35138753210820096000, 2213741452281666048000, 159389384564279955456000

Offset: 1

Author

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

Keywords

• easy
• nonn
• base

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..250

Crossrefs

Cf. A047892 (start=2), A047912 (start=3), A047897 (start=5), A047899 (start=7), A047900 (start=8), A047901 (start=9), A047902 (start=11).

Programs

Haskell

a047898 n = a047898_list !! (n-1)
a047898_list = iterate a057147 6  -- Reinhard Zumkeller, Mar 19 2014

Mathematica

Nest[Append[#, # Total@ IntegerDigits@ # &@ Last[#]] &, {6}, 15] (* Michael De Vlieger, Jul 08 2019 *)

Python

A047898_list, l = [6], 6
for _ in range(10**2):
    l *= sum(int(d) for d in str(l))
    A047898_list.append(l) # Chai Wah Wu, Jan 04 2015

Formula

a(n+1) = A057147(a(n)). - Reinhard Zumkeller, Mar 19 2014