A111298 Begin with first number 15. Add the digits of the first number to give the second; the first number multiplied by the second gives the third. The third number becomes the first in a new "set" of three.

15, 6, 90, 9, 810, 9, 7290, 18, 131220, 9, 1180980, 27, 31886460, 36, 1147912560, 36, 41324852160, 36, 1487694677760, 72, 107114016798720, 54, 5784156907130880, 72, 416459297313423360, 72, 29985069406566481920, 99, 2968521871250081710080

Offset

0,1

Links

Table of n, a(n) for n=0..28.

Mathematica

a[0]=15; Do[a[n]=Total[IntegerDigits[a[n-1]]]; a[n+1]=a[n-1]*a[n], {n, 1, 28, 2}]; Table[a[n], {n, 0, 28}] (* James C. McMahon, May 07 2024 *)

Crossrefs

Sequence in context: A277384 A040214 A364351 * A241440 A040213 A362409

Adjacent sequences: A111295 A111296 A111297 * A111299 A111300 A111301

Keyword

nonn,base

Author

Chris Dawson (chris(AT)irjsoftware.com), based on an email from Graham Rees, Nov 02 2005

Extensions

More terms from R. J. Mathar, Feb 08 2008

Name edited by Michel Marcus, May 08 2024

Status

approved