A047900 a(1) = 8; for n > 0, a(n+1) = a(n) * sum of digits of a(n).

8, 64, 640, 6400, 64000, 640000, 6400000, 64000000, 640000000, 6400000000, 64000000000, 640000000000, 6400000000000, 64000000000000, 640000000000000, 6400000000000000, 64000000000000000, 640000000000000000

Offset

1,1

Comments

After the 2nd element, every element has the same beginning.

a(3+k) = 10 * a(2+k).

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[#]]&, 8, 20] (* or *) Join[{8}, NestList[ 10#&, 64, 20]] (* Harvey P. Dale, Jul 03 2020 *)

Prog

(Haskell)
a047900 n = a047900_list !! (n-1)
a047900_list = iterate a057147 8  -- Reinhard Zumkeller, Mar 19 2014

Crossrefs

Cf. A047892 (start=2), A047912 (start=3), A047897 (start=5), A047898 (start=6), A047899 (start=7), A047901 (start=9), A047902 (start=11).

Sequence in context: A213336 A366497 A355214 * A204212 A238724 A318640

Adjacent sequences: A047897 A047898 A047899 * A047901 A047902 A047903

Keyword

easy,nonn,base

Author

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

Status

approved