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Fold a square sheet of paper alternately vertically to the left and horizontally downwards; after each fold, draw a line along each inward crease; after n folds, we obtain a graph G(n); G(n) is contained with G(n+1); let H be the limit of G(n) as n tends to infinity; a(n) is the number of nodes of degree 1 or 3 that are at distance n from the origin in H; a(0) = 1.
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%I #7 Mar 31 2021 20:28:41

%S 1,2,3,4,6,7,9,9,10,14,19,17,16,20,20,22,23,23,29,39,27,29,32,33,38,

%T 36,36,40,38,37,45,44,42,42,47,58,63,62,59,55,50,51,54,58,55,59,74,72,

%U 73,77,64,65,72,62,67,68,61,75,80,89,75,74,70,76,76,79,79

%N Fold a square sheet of paper alternately vertically to the left and horizontally downwards; after each fold, draw a line along each inward crease; after n folds, we obtain a graph G(n); G(n) is contained with G(n+1); let H be the limit of G(n) as n tends to infinity; a(n) is the number of nodes of degree 1 or 3 that are at distance n from the origin in H; a(0) = 1.

%C A342759 is the main sequence for this entry.

%H Rémy Sigrist, <a href="/A342760/a342760.png">Illustration of initial terms</a>

%H Rémy Sigrist, <a href="/A342760/a342760_1.png">Colored representation of the nodes at distance <= 512</a> (where the color is function of the distance)

%H Rémy Sigrist, <a href="/A342760/a342760.txt">C# program for A342760</a>

%H <a href="/index/Con#coordination_sequences">Index entries for coordination sequences</a>

%e See illustration in Links section.

%o (C#) See Links section.

%Y Cf. A342759.

%K nonn

%O 0,2

%A _Rémy Sigrist_, Mar 30 2021