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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A090072 Numbers n such that there are (presumably) eleven palindromes in the Reverse and Add! trajectory of n. 2
1, 20000, 20002, 1000000, 1000001, 10000000, 10000001 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Additional terms (cf. A090075) are 100000000, 100000001, 100010001, 1000000000, 1000000001, 10000000000, 10000000001, 100000000000, 100000000001, 1000000000000, 1000000000001, 1000001000001, 1000100010001, but it is not yet ascertained that they are consecutive.

For all terms given above each palindrome is reached from the preceding one or from the start in at most 35 steps; after the presumably last one no further palindrome is reached in 5000 steps.

Only two numbers are known whose Reverse and Add trajectory contains twelve palindromes: 10000 and 10001. It is conjectured that these are the only such numbers and it has been conjectured before (cf. A077594) that no Reverse and Add trajectory contains more than twelve palindromes.

LINKS

Index entries for sequences related to Reverse and Add!

EXAMPLE

The trajectory of 1 begins 1, 2, 4, 8, 16, 77, 154, 605, 1111, 2222, 4444, 8888, 17776, 85547, 160105, 661166, 1322332, 3654563, 7309126, ...; at 7309126 it joins the (presumably) palindrome-free trajectory of A063048(7) = 10577, hence

1, 2, 4, 8, 77, 1111, 2222, 4444, 8888, 661166 and 3654563 are the eleven palindromes in the trajectory of 1 and 1 is a term.

CROSSREFS

Cf. A023108, A023109, A065001, A070742, A077594, A090075.

Sequence in context: A175590 A203045 A206009 * A035926 A186565 A186480

Adjacent sequences:  A090069 A090070 A090071 * A090073 A090074 A090075

KEYWORD

nonn,base

AUTHOR

Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 20 2003

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 16 16:00 EST 2012. Contains 205938 sequences.