A121111 Trajectory of 277777788888899 under "x -> product of digits of x" map.

277777788888899, 4996238671872, 438939648, 4478976, 338688, 27648, 2688, 768, 336, 54, 20, 0

Offset: 1

Author

N. J. A. Sloane, Aug 12 2006

Keywords

• nonn
• fini
• full
• base

Comments

This is the smallest number of persistence 11 (cf. A003001). It is conjectured that no number has persistence greater than 11.

Links

• N. J. A. Sloane, The persistence of a number, J. Recreational Math., 6 (1973), 97-98.

Crossrefs

Cf. A003001.

Programs

Mathematica

NestWhileList[Times@@IntegerDigits[#]&,277777788888899,#>0&] (* Harvey P. Dale, Nov 25 2022 *)

Formula

a(n)=A121110(n-1), n>=3. [From R. J. Mathar, Aug 07 2008]

Extensions

Edited by Charles R Greathouse IV, Aug 05 2010