A346821 - OEIS

%I #18 Aug 30 2021 21:40:52

%S 1,10,11,101,10111,101101,11101,11101101,1110111,10110111,

%T 1011011110111,10110111101101,1110111101101,111011110110111101101,

%U 11101111011011110111,101101111011011110111,1011011110110111101111011011110111,10110111101101111011110110111101101,1110111101101111011110110111101101

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

%C 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.

%e a(1) = 1, a(2) = 10, a(3) = 11 form the palindrome 11011 when concatenated;

%e a(2) = 10, a(3) = 11, a(4) = 101 form the palindrome 1011101 when concatenated;

%e a(3) = 11, a(4) = 101, a(5) = 10111 form the palindrome 1110110111 when concatenated;

%e a(4) = 101, a(5) = 10111, a(6) = 101101 form the palindrome 10110111101101 when concatenated; etc.

%Y Cf. A000042.

%K base,nonn

%O 1,2

%A _Eric Angelini_ and _Carole Dubois_, Aug 30 2021