A114120 Palindromes which are not the arithmetic mean of two distinct positive palindromes.

1, 11, 10901, 109901, 1090901, 1099901, 10900901, 10999901, 100909001, 109000901, 109090901, 109909901, 109999901, 1090000901, 1090990901, 1099009901, 1099999901, 10090909001, 10900000901, 10900900901, 10909090901, 10909990901

Offset

1,2

Comments

In this sequence 0 is not allowed as an addend. If 0 were allowed then 0 would be a term and 1 and 11 would not. - Yuan-Hao Huang, Aug 31 2020

Links

Table of n, a(n) for n=1..22.

Example

191 is not in the sequence since it is the arithmetic mean of two distinct positive palindromes, 9 and 373.

Crossrefs

Cf. A002113, A083158.

Sequence in context: A121520 A308335 A083442 * A118557 A267273 A138713

Adjacent sequences: A114117 A114118 A114119 * A114121 A114122 A114123

Keyword

base,nonn

Author

Giovanni Resta, Feb 06 2006

Extensions

a(1)=1 inserted by Yuan-Hao Huang, Aug 31 2020

Status

approved