A261906 Numbers that are the sum of two nonzero palindromes.

2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 112, 113, 114, 115, 116, 117, 118, 119, 120

Offset: 1

Author

N. J. A. Sloane, Sep 09 2015

Keywords

• nonn
• base

Comments

More than the usual number of terms are shown in order to distinguish this from A260255.

Examples

			22 is a member because it is the sum of two palindromes, 11+11 (not because it is a palindrome in its own right).
111 is not the sum of two nonzero palindromes, so appears in A260255 but not here. See A213879 for further differences between the two sequences.
		

Crossrefs

Cf. A002113, A260255, A213879.

Programs

Maple

# Sums of two nonzero pals:
# bP has a list of palindromes starting at 0.
a2:={}; M:=60; M2:=bP[M];
for i from 2 to M do
for j from i to M do
k:=bP[i]+bP[j];
if k <= M2 then a2:={op(a2),k}; fi;
od: od:
b2:=sort(convert(a2,list));

Mathematica

Take[Total/@Tuples[Select[Range[200],PalindromeQ],2]//Union,120] (* Harvey P. Dale, Apr 27 2025 *)