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

Author

Eric Angelini and Carole Dubois, Aug 30 2021

Keywords

• base
• nonn

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.

Examples

			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.