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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A045571 Numbers that are palindromic, divisible by 11 and have an odd number of digits. 1
 121, 242, 363, 484, 616, 737, 858, 979, 10901, 11011, 12221, 13431, 14641, 15851, 17171, 18381, 19591, 20702, 21912, 22022, 23232, 24442, 25652, 26862, 28182, 29392, 30503, 31713, 32923, 33033, 34243, 35453, 36663, 37873, 39193, 40304 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All the palindromic numbers with an even number of digits are divisible by 11. The number of palindromic numbers with 2*k+1 digits that are divisible by 11 is (10^(k+1) + (-1)^k)/11, and their asymptotic relative density within the set of all palindromic numbers with an odd number of digits (A056525) is 1/11 (Schmidt, 1988). - Amiram Eldar, Jan 11 2021 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 Harvey Schmidt, Jr., Palindromes: Density and Divisibility, Mathematics Magazine, Vol. 61, No. 5 (1988), pp. 297-300. MATHEMATICA Select[11 * Range[4000], PalindromeQ[#] && OddQ[IntegerLength[#]] &] (* Amiram Eldar, Jan 11 2021 *) CROSSREFS Intersection of A056525 and A083852. Sequence in context: A084998 A082944 A131973 * A088285 A218172 A083749 Adjacent sequences: A045568 A045569 A045570 * A045572 A045573 A045574 KEYWORD base,nonn AUTHOR Jeff Burch 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.

Last modified November 28 18:35 EST 2023. Contains 367419 sequences. (Running on oeis4.)