login
This site is supported by donations to The OEIS Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A100761 Beginning with 1, the smallest positive number which when appended to the reverse concatenation of all previous terms gives a multiple of n. 0

%I

%S 1,2,3,2,5,2,3,6,3,10,4,16,22,6,5,6,2,10,15,20,25,30,12,6,25,2,9,2,2,

%T 20,34,28,16,22,30,44,17,46,48,20,47,44,34,32,45,24,35,28,38,50,47,24,

%U 1,50,20,36,1,34,51,20,35,34,66,28,60,38,16,32,33,50,3,28,66,66,75,12,4,26

%N Beginning with 1, the smallest positive number which when appended to the reverse concatenation of all previous terms gives a multiple of n.

%e a(2) = 2, 2 divides 12, a(3) = 3, 213 is a multiple of 3, a(4) = 2, 3212 is a multiple of 4.

%e a(11) = 4, 103632523214 == 0 (mod 11) where 103632523214 is 10363252321 followed by a 4.

%t a[1] = 1; a[n_] := a[n] = Block[{k = 1, t = Flatten[ Table[ IntegerDigits[ a[n - i]], {i, n - 1}]]}, While[ Mod[ FromDigits[ Join[t, IntegerDigits[k]]], n] != 0, k++ ]; k]; Table[ a[n], {n, 78}] (* _Robert G. Wilson v_, Nov 26 2004 *)

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Nov 25 2004

%E More terms from _Robert G. Wilson v_, Nov 26 2004

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 20 02:13 EST 2019. Contains 319320 sequences. (Running on oeis4.)