A047912 a(1) = 3; for n > 0, a(n+1) = a(n) * sum of digits of a(n).

3, 9, 81, 729, 13122, 118098, 3188646, 114791256, 4132485216, 148769467776, 10711401679872, 578415690713088, 41645929731342336, 2998506940656648192, 296852187125008171008, 24045027157125661851648

Offset

1,1

Comments

Apart from the first term, the same as A047901. - R. J. Mathar, Oct 18 2008

Links

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

Formula

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

Mathematica

NestList[# Total[IntegerDigits[#]]&, 3, 20]  (* Harvey P. Dale, Mar 21 2011 *)

Prog

(Haskell)
a047912 n = a047912_list !! (n-1)
a047912_list = iterate a057147 3  -- Reinhard Zumkeller, Mar 19 2014

Crossrefs

Cf. A047892 (start=2), A047897 (start=5), A047898 (start=6), A047899 (start=7), A047900 (start=8), A047901 (start=9), A047902 (start=11).

Sequence in context: A067623 A171557 A055156 * A078684 A121858 A215114

Adjacent sequences: A047909 A047910 A047911 * A047913 A047914 A047915

Keyword

easy,nice,nonn,base

Author

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

Status

approved