A346821 Lexicographically earliest sequence of distinct terms > 0 such that the concatenation of three successive terms form a palindrome in base 10.

1, 10, 11, 101, 10111, 101101, 11101, 11101101, 1110111, 10110111, 1011011110111, 10110111101101, 1110111101101, 111011110110111101101, 11101111011011110111, 101101111011011110111, 1011011110110111101111011011110111, 10110111101101111011110110111101101, 1110111101101111011110110111101101

Offset

1,2

Comments

This sequence shows only 0's and 1's. The lexicographically earliest sequence of distinct terms > 0 such that the concatenation of two successive terms form a palindrome in base 10 is A000042.

Links

Table of n, a(n) for n=1..19.

Example

a(1) = 1, a(2) = 10, a(3) = 11 form the palindrome 11011 when concatenated;
a(2) = 10, a(3) = 11, a(4) = 101 form the palindrome 1011101 when concatenated;
a(3) = 11, a(4) = 101, a(5) = 10111 form the palindrome 1110110111 when concatenated;
a(4) = 101, a(5) = 10111, a(6) = 101101 form the palindrome 10110111101101 when concatenated; etc.

Crossrefs

Cf. A000042.

Sequence in context: A004685 A361335 A171000 * A222365 A041216 A094026

Adjacent sequences: A346818 A346819 A346820 * A346822 A346823 A346824

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Aug 30 2021

Status

approved