

A261924


Numbers that are the sum of two palindromes of the same length.


2



0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 22, 33, 44, 55, 66, 77, 88, 99, 110, 121, 132, 143, 154, 165, 176, 187, 198, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 302, 303, 312, 313, 322, 323, 332, 333, 342, 343, 352, 353, 362, 363, 372, 373, 382, 383, 393
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OFFSET

1,3


COMMENTS

Theorem: For a fixed value of d, adding two palindromes of length d in all possible ways produces 19 distinct sums if d=1, and 17*19^floor((d1)/2) distinct sums if d>1. (The number of palindromes with d digits is 10 if d = 1, otherwise 9*10^floor((d1)/2).)  N. J. A. Sloane, Dec 06 2015


LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..12956


CROSSREFS

Cf. A002113, A261921, A261925, etc.
Sequence in context: A246086 A194417 A246093 * A255421 A255407 A269171
Adjacent sequences: A261921 A261922 A261923 * A261925 A261926 A261927


KEYWORD

nonn,base


AUTHOR

David Applegate and N. J. A. Sloane, Sep 17 2015


EXTENSIONS

Modified to include the zero palindrome.  N. J. A. Sloane, Dec 06 2015


STATUS

approved



