|
%I #15 Sep 29 2023 07:09:36
%S 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,
%T 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,
%U 16,17,10,11,12,13,14,15,16,17,18,19,12,13,14,15,16,17
%N a(n) is the sum of the digits of n-th base 10 palindrome.
%H David A. Corneth, <a href="/A043269/b043269.txt">Table of n, a(n) for n = 1..10000</a>
%e 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.
%t Total[IntegerDigits[#]]&/@Select[Range[0,750],PalindromeQ] (* _Harvey P. Dale_, Feb 11 2022 *)
%o (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
%Y Cf. A002113 (base 10 palindromes).
%K nonn,easy,base
%O 1,3
%A _Clark Kimberling_
|
