OFFSET
1,1
COMMENTS
Each term is created by calculating the sum of the digits of the previous number, and the product of its digits. The results are concatenated to give the new number. Starting with 6, the second number is 66. The third number is generated as follows: 6+6=12, 6*6=36, which gives 1236. After that, the numbers remain unchanged, because 1+2+3+6=12 and 1x2x3x6=36, so combined 1236 again.
MATHEMATICA
NestList[FromDigits[Flatten@ {IntegerDigits@ Total@ #, IntegerDigits@ If[Length@ # == 1, #, Times @@ #]}] &@ IntegerDigits@ # &, 6, 50] (* Michael De Vlieger, Apr 02 2016 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Sander Claassen, Apr 02 2016
STATUS
approved