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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A248754 Palindromes p=A002113(n) whose index n is also a palindrome and in addition a substring of p (strings in base 10). 1
11, 1111, 12221, 23332, 34443, 45554, 56665, 67776, 78887, 89998, 111111, 1222221, 2333332, 3444443, 4555554, 5666665, 6777776, 7888887, 8999998, 9101019, 11111111, 102020201, 112121211, 122222221, 132323231, 142424241, 152525251, 162626261, 172727271, 182828281 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
This is a proper subsequence of A248753 (where the index does not need to be palindromic).
LINKS
EXAMPLE
11 is a term because the eleventh palindrome is 11.
1111 is a member because it is the 111th palindrome.
12221 is in the sequence because the 222nd palindrome is 12221.
MATHEMATICA
(* first load 'nthPalindrome' from A002113 and then *) nPal[n_] := nthPalindrome[n - 1]; fQ[n_] := StringPosition[ ToString[ nPal[ nPal[ k]]], ToString[ nPal[ n]]] != {}; k = 2; lst = {}; While[k < 501, If[ fQ[k], AppendTo[lst, nPal[ nPal[ k]] ]]; k++]; lst
CROSSREFS
Sequence in context: A289934 A289968 A248753 * A099814 A340549 A260077
KEYWORD
nonn,base,easy
AUTHOR
Robert G. Wilson v, Oct 13 2014
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 March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)