A080263 A014486-encoding of the branch-reduced binomial-mod-2 binary trees.

2, 50, 906, 247986, 4072138, 1059204274, 272900475786, 17953590946285746, 287705670922216138, 73724537815637830834, 18880972926031430339466, 1237678872789190922262530226, 316876593058175709191975346890

Offset

0,1

Comments

These trees are obtained from the successive generations of Rule 90 cellular automaton (A070886) or Pascal's triangle computed modulo 2 (A047999), with alive cells of the automaton (respectively: the odd binomials) forming the vertices of the zigzag tree.

References

J. C. P. Miller, Periodic Forests of Stunted Trees, Phil. Tran. Roy. Soc. London A266 (1970) 63; A293 (1980) 48.

Links

Table of n, a(n) for n=0..12.

A. Karttunen, Initial terms illustrated

Crossrefs

Same sequence in binary: A080264. Cf. A080265. Breadth-first-wise encodings of the same trees: A080268. Corresponding branch-reduced zigzag trees: A080293.

Number of edges in general trees/internal nodes in binary trees: A006046, number of zigzag-edges (those colored black in illustrations) is one less: A074330. Cf. A080978.

Sequence in context: A080299 A083939 A083941 * A221241 A246071 A367777

Adjacent sequences: A080260 A080261 A080262 * A080264 A080265 A080266

Keyword

nonn

Author

Antti Karttunen, Mar 02 2003

Status

approved