login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A125886 a(1) = 1, a(n) = smallest positive number b not among a(1)..a(n-1) such that the last digit of b = the first digit of a(n-1). 3
1, 11, 21, 12, 31, 13, 41, 14, 51, 15, 61, 16, 71, 17, 81, 18, 91, 19, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 22, 32, 23, 42, 24, 52, 25, 62, 26, 72, 27, 82, 28, 92, 29, 102, 211, 112, 221, 122, 231, 132, 241, 142, 251, 152, 261, 162, 271, 172, 281, 182 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A dyslexic person might have trouble distinguishing this sequence from A125887!

A010879(a(n+1)) = A000030(a(n)). - Reinhard Zumkeller, Aug 10 2014

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Hans Havermann, Graph of first 10000 terms

MATHEMATICA

s={1}; fi=1; Do[Do[id=IntegerDigits[i]; la=id[[ -1]]; If[fi==la&&FreeQ[s, i], AppendTo[s, i]; fi=id[[1]]; Break[]], {i, 11, 10^5}], {999}]; s

PROG

(Haskell)

import Data.List (delete)

a125886 n = a125886_list !! (n-1)

a125886_list = 1 : f 1 [10..] where

f u vs = g vs where

g (w:ws) = if a010879 w == iu then w : f w (delete w vs) else g ws

iu = a000030 u

-- Reinhard Zumkeller, Aug 10 2014

CROSSREFS

Cf. A125887.

Cf. A000030, A010879.

Sequence in context: A061384 A071154 A071161 * A067574 A299400 A300296

Adjacent sequences: A125883 A125884 A125885 * A125887 A125888 A125889

KEYWORD

base,nonn,look,hear

AUTHOR

Zak Seidov, Dec 13 2006

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 9 23:05 EST 2022. Contains 358710 sequences. (Running on oeis4.)