A330622 - OEIS

%I #11 Dec 26 2019 05:44:50

%S 0,0,1,0,0,1,2,2,3,0,0,3,0,0,4,2,5,3,5,6,3,4,4,6,6,5,4,0,0,7,0,0,7,8,

%T 8,9,0,0,7,0,0,3,8,5,3,5,9,9,5,8,7,9,2,7,10,4,3,10,6,7,6,10,10,6,6,4,

%U 10,4,9,6,11,6,6,8,11,5,8,8,4,10,11,0,0,7

%N Lexicographically earliest sequence of nonnegative terms such that for any n > 0 and k > 0, a(n+2*k) <> gcd(a(n), a(n+k)).

%C This sequence differs radically from the variant where we consider only positive terms (A330623).

%H Rémy Sigrist, <a href="/A330622/b330622.txt">Table of n, a(n) for n = 1..10000</a>

%H Rémy Sigrist, <a href="/A330622/a330622.png">Scatterplot of the first 250000 terms</a>

%H Rémy Sigrist, <a href="/A330622/a330622.txt">C program for A330622</a>

%F a(n) = 0 iff n belongs to A003278.

%o (C) See Links section.

%Y Cf. A003278 (positions of 0's), A330623 (positive variant).

%Y See A330267 for similar sequences.

%K nonn

%O 1,7

%A _Rémy Sigrist_, Dec 21 2019