[seqfan] Divisibility by odd/even numbers

Eric Angelini Eric.Angelini at kntv.be
Sun Apr 12 17:53:39 CEST 2015


Hello SeqFans,
according to http://oeis.org/A005408
(the odd numbers), the first odd number
is 1, and according to http://oeis.org/A005843
(the even numbers), the second even
number is 2.

We could thus look for (zeroless) integers
that could be devided by the first odd 
number, or the second even number,
or the third odd number, or the fourth
even number, etc. -- depending on
the digits that are used to write the
said integer.

I guess the Pa (parity) sequence would
start like this:

Pa = 1,2,11,12,22,24,28,42,54,84,111,
112.114,117,122,135,...

Tab:
1-1
2-2
3-5
4-6
5-9
6-10
7-13
8-14
9-17

Examples:

54 is divisible by the 5th odd number (9);
54 is divisible by the 4th even number (6);

135 is divisible by the 1st odd number (1);
135 is divisible by the 3rd odd number (5);
135 is divisible by the 5th odd number (9).
 
Best,
É.



More information about the SeqFan mailing list