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A331880 Lexicographically earliest sequence of distinct positive integers such that (last digit of a(n)) > (first digit of a(n+1)). 2

%I #11 Jan 31 2020 20:30:48

%S 2,12,13,14,3,15,4,16,5,17,6,18,7,19,8,22,102,103,23,24,25,26,27,28,

%T 29,32,104,33,105,34,35,36,37,38,39,42,106,43,107,44,108,45,46,47,48,

%U 49,52,109,53,112,113,114,115,116,54,117,55,118,56,57,58,59,62,119,63,122,123,124,125,126,127,64,128,65

%N Lexicographically earliest sequence of distinct positive integers such that (last digit of a(n)) > (first digit of a(n+1)).

%C No integer ending in 0 or 1 is a member of the sequence.

%H Carole Dubois, <a href="/A331880/b331880.txt">Table of n, a(n) for n = 1..14685</a>

%e a(1) cannot be 1 as there is no a(2) whose first digit would be 0

%e a(1) = 2 and 2 (the last digit) is > 1, this 1 being the first digit of a(2) = 12

%e a(2) = 12 and 2 (the last digit) is > 1, this 1 being the first digit of a(3) = 13

%e a(3) = 13 and 3 (the last digit) is > 1, this 1 being the first digit of a(4) = 14

%e a(4) = 14 and 4 (the last digit) is > 3, this 3 being the first digit of a(5) = 3; etc.

%Y Cf. A331879 for the variant where the last digit of a(n) is < than the first digit of a(n+1).

%K base,nonn

%O 1,1

%A _Eric Angelini_ and _Carole Dubois_, Jan 30 2020

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Last modified April 23 03:30 EDT 2024. Contains 371906 sequences. (Running on oeis4.)