A335043 - OEIS

A335043

Lexicographically earliest sequence of distinct positive integers such that for any n > 0, the decimal representations of a(2*n-1) and of a(2*n+1) appear as substrings in the decimal representation of a(2*n).

%I #24 Jun 02 2020 14:10:33

%S 1,12,2,23,3,34,4,45,5,56,6,67,7,78,8,89,9,109,10,110,11,113,13,130,

%T 30,330,33,331,31,314,14,140,40,240,24,224,22,220,20,320,32,321,21,

%U 215,15,150,50,250,25,251,51,351,35,352,52,526,26,260,60,160,16,161

%N Lexicographically earliest sequence of distinct positive integers such that for any n > 0, the decimal representations of a(2*n-1) and of a(2*n+1) appear as substrings in the decimal representation of a(2*n).

%C This sequence has similarities with A281978; here we look for substrings, there for divisors.

%C This sequence has similarities with A262323: in both sequences, consecutive terms overlap.

%H Rémy Sigrist, <a href="/A335043/b335043.txt">Table of n, a(n) for n = 1..10001</a>

%H Rémy Sigrist, <a href="/A335043/a335043.png">Colored logarithmic scatterplot of the first 10001 terms</a> (where the color denotes the parity of n)

%H Rémy Sigrist, <a href="/A335043/a335043.gp.txt">PARI program for A335043</a>

%e The first terms are:

%e n a(n)

%e -- ------

%e 1 1

%e 2 12

%e 3 2

%e 4 23

%e 5 3

%e 6 34

%e 7 4

%e 8 45

%e 9 5

%e 10 56

%e 11 6

%o (PARI) See Links section.

%Y Cf. A262323, A281978.

%K nonn,base

%O 1,2

%A _Rémy Sigrist_, Jun 01 2020