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Lexicographically earliest sequence of distinct positive terms ending in their digital root such that the result of a(n) + a(n+1) also ends in its digital root.
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%I #10 May 30 2020 15:05:04

%S 1,2,3,4,5,91,6,92,7,181,8,271,93,94,95,182,96,183,184,185,272,97,361,

%T 98,451,186,273,274,275,362,187,452,276,363,364,365,453,366,541,188,

%U 631,277,542,367,632,454,455,543,456,633,544,545,634,635,721,278,811,368,901,457,722,546,723,636,812

%N Lexicographically earliest sequence of distinct positive terms ending in their digital root such that the result of a(n) + a(n+1) also ends in its digital root.

%H Jean-Marc Falcoz, <a href="/A334536/b334536.txt">Table of n, a(n) for n = 1..2000</a>

%e a(5) = 5 ends with 5, its digital root;

%e a(6) = 91 ends with 1, its digital root;

%e a(5) + a(6) = 96 also ends with its digital root.

%Y Cf. A010888, A280658.

%K base,nonn

%O 1,2

%A _Eric Angelini_ and _Jean-Marc Falcoz_, May 05 2020