aparler/RosettaCodeData
1
0
Fork 0
Code Issues 12 Pull requests 3 Projects Releases Packages Wiki Activity Actions

update meta data

Browse source
This commit is contained in:
Ingy döt Net 2013-04-11 12:07:39 -07:00
parent f3a896c724
commit 90e15ed6ce
3307 changed files with 1674 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

20
Task/Digital-root/00DESCRIPTION Normal file
View file

@ -0,0 +1,20 @@
Related task [[Sum digits of an integer]]
The digital root (X) of a number (N) is calculated:
: find X as the sum of the digits of N
: find a new X by summing the digits of X repeating until X has only one digit.
The additive persistence is the number of summations required to obtain the single digit.
The task is to calculate the additive persistence and the digital root of a number. e.g.
:627615 has additive persistence 2 and digital root of 9;
:39390 has additive persistence 2 and digital root of 6;
:588225 has additive persistence 2 and digital root of 3;
:393900588225 has additive persistence 2 and digital root of 9;
The digital root may be calculated in bases other than 10.
See:
*[[Casting out nines]] for this wiki's use of this procedure.
*[[oeis:A010888|Digital root sequence on OEIS]]
*[[oeis:A031286|Additive persistence sequence on OEIS]]