Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A093017
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A093017 Luhn algorithm double-and-add sum of digits of n. +0
13
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 7, 8, 9, 10, 11, 12, 13 (list; graph; listen)
OFFSET

0,3

COMMENT

Starting on the right, sum digits after doubling alternating digits beginning with the second. If doubled digit >9, reduce by 9 (sum of digits).

LINKS

John Kilgo, DotNetJohn.com, Using the Luhn Algorithm

Webopedia, Luhn formula

EXAMPLE

a(18) = 2*1 + 8 = 10.

a(59) = (1+0) + 9 = 10 (1 and 0 are the digits in 10 = 2*5).

CROSSREFS

Cf. A093018-A093029.

Sequence in context: A061816 A083960 A138795 this_sequence A028897 A156230 A081594

Adjacent sequences: A093014 A093015 A093016 this_sequence A093018 A093019 A093020

KEYWORD

easy,nonn,base

AUTHOR

Ray Chandler (rayjchandler(AT)sbcglobal.net), Apr 3 2004

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 23 17:09 EST 2009. Contains 167438 sequences.


AT&T Labs Research