login
A126304
a(n) = number of nodes with nonzero even distance to the root in the n-th plane general tree encoded by A014486(n).
4
0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 1, 1, 2, 1, 1, 2, 2, 3, 2, 1, 2, 1, 2, 0, 1, 1, 2, 1, 1, 2, 2, 3, 2, 1, 2, 1, 2, 1, 2, 2, 3, 2, 2, 3, 3, 4, 3, 2, 3, 2, 3, 1, 2, 2, 3, 2, 1, 2, 1, 2, 2, 3, 2, 3, 2, 0, 1, 1, 2, 1, 1, 2, 2, 3, 2, 1, 2, 1, 2, 1, 2, 2, 3, 2, 2, 3, 3, 4, 3, 2, 3, 2, 3, 1, 2, 2, 3, 2, 1, 2, 1, 2
OFFSET
0,8
EXAMPLE
A014486(27) = 696 (1010111000 in binary), encodes the following general plane tree, where the root is marked with * and nodes with even or odd distance to root with 'e's and 'o's, respectively.
.......o
.......|
.......e
.......|
...o.o.o
....\|/.
.....*..
there is one node marked with 'e', thus a(27)=1.
PROG
(Scheme:) (define (A126304 n) (*A126304 (A014486->parenthesization (A014486 n))))
(define (*A126304 s) (cond ((null? s) 0) (else (apply + (map *A126303 s)))))
CROSSREFS
a(n) = A126305(n)-1. Cf. A126303. Scheme-function A014486->parenthesization given in A014486.
Sequence in context: A293461 A255482 A204172 * A280522 A324796 A049455
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 02 2007
STATUS
approved