A047903 a(1) = 13; for n > 0, a(n+1) = a(n) * sum of digits of a(n).

13, 52, 364, 4732, 75712, 1665664, 56632576, 2265303040, 56632576000, 2265303040000, 56632576000000, 2265303040000000, 56632576000000000, 2265303040000000000, 56632576000000000000, 2265303040000000000000

Offset

1,1

Comments

After the 7th element, every second element has the same beginning. a(9+2k) = 40 * a(8+2k) = 40 * 25 * a(7+2k).

Links

Table of n, a(n) for n=1..16.

Mathematica

NestList[# Total[IntegerDigits[#]]&, 13, 20] (* Harvey P. Dale, Jan 08 2019 *)

Crossrefs

Cf. A047892.

Sequence in context: A022673 A152742 A213837 * A197790 A317467 A076163

Adjacent sequences: A047900 A047901 A047902 * A047904 A047905 A047906

Keyword

easy,nonn,base

Author

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

Status

approved