A043269 a(n) is the sum of the digits of n-th base 10 palindrome.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 2, 4, 6, 8, 10, 12, 14, 16, 18, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 12, 13, 14, 15, 16, 17

Offset

1,3

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

Example

For n = 36, the n-th palindrome is the 36-th palindrome i.e., 262. The sum of digits of 262 (in base 10) is 2 + 6 + 2 = 10 hence a(36) = 10.

Mathematica

Total[IntegerDigits[#]]&/@Select[Range[0, 750], PalindromeQ] (* Harvey P. Dale, Feb 11 2022 *)

Prog

(PARI) a(n)={my(d, i, r); r=vector(#digits(n-10^(#digits(n\11)))+#digits(n\11)); n=n-10^(#digits(n\11)); d=digits(n); for(i=1, #d, r[i]=d[i]; r[#r+1-i]=d[i]); vecsum(r)} \\ David A. Corneth, Sep 29 2023

Crossrefs

Cf. A002113 (base 10 palindromes).

Sequence in context: A080719 A049105 A125959 * A122481 A110805 A356234

Adjacent sequences: A043266 A043267 A043268 * A043270 A043271 A043272

Keyword

nonn,easy,base

Author

Clark Kimberling

Status

approved