A332970 - OEIS

A332970

Colombian palindromes.

1, 3, 5, 7, 9, 121, 222, 323, 424, 525, 626, 727, 828, 929, 1111, 2112, 3113, 4114, 5115, 6116, 7117, 8118, 9119, 10401, 11211, 12921, 13731, 14541, 15351, 16161, 18881, 19691, 20402, 21212, 22922, 23732, 24542, 25352, 26162, 28882, 29692, 30403, 31213, 32923

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OFFSET

1,2

COMMENTS

Palindromes that are not the sum of an integer and of the individual digits of this integer (see Wikipedia link).

LINKS

Table of n, a(n) for n=1..44.

Wikipedia, Self number or Colombian number

Wikipedia, Palindromic number

Index to sequences related to Colombian numbers

Index to sequences related to palindromes

EXAMPLE

323 is a palindrome that cannot be written as the sum of any other natural number k and the digits of k, hence 323 that is Colombian number in base 10 is a term.

333 is a palindrome but 333 = 324 + 3 + 2 + 4, hence 333 that is not a self number in base 10 is not a term.

MATHEMATICA

n = 33000; Select[Complement[Range[n], Union @ Table[Plus @@ IntegerDigits[k] + k, {k, 1, n}]], PalindromeQ] (* Amiram Eldar, Mar 04 2020 *)

CROSSREFS

Intersection of A002113 (palindromes) and A003052 (Colombians).

Complement of A332240 relative to A002113.

Sequence in context: A030148 A364836 A068061 * A316492 A062887 A062886

Adjacent sequences: A332967 A332968 A332969 * A332971 A332972 A332973

KEYWORD

nonn,base

AUTHOR

Bernard Schott, Mar 04 2020

EXTENSIONS

More terms from Amiram Eldar, Mar 04 2020

STATUS

approved