login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A335978 Numbers m of the form abs(k - reverse(k)) for at least one k. 1
0, 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 180, 189, 198, 270, 279, 297, 360, 369, 396, 450, 459, 495, 540, 549, 594, 630, 639, 693, 720, 729, 792, 810, 819, 891, 900, 909, 990, 999, 1089, 1179, 1188, 1269, 1278, 1359, 1368, 1449, 1458, 1539, 1548, 1629, 1638, 1719, 1728, 1800, 1809, 1818, 1890, 1908, 1980, 1989, 1998, 2079 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

All terms are divisible by 9.

Let f(k) = k - reverse(k). Then f(reverse(k)) = -f(k), since f(reverse(k)) = reverse(k) - reverse(reverse(k)) = reverse(k) - k = - (k - reverse(k)) = -f(k).

Iteration of the function f(k) = k - reverse(k) leads to A072140, A072141, A072142, and A072143.

LINKS

Table of n, a(n) for n=1..64.

Michael P. Greaney, Remarkable Reversible Numbers, +plus magazine, (September 29, 2015).

CROSSREFS

Cf. A056965, A067030, A072140, A072141, A072142, A072143.

Dividing by 9 gives A334145.

Sequence in context: A070279 A259729 A016096 * A070793 A052223 A085132

Adjacent sequences:  A335975 A335976 A335977 * A335979 A335980 A335981

KEYWORD

nonn,base

AUTHOR

Michael Greaney, Jul 03 2020

STATUS

approved

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 October 19 17:24 EDT 2021. Contains 348091 sequences. (Running on oeis4.)