OFFSET
0,3
LINKS
PROG
(Scheme function, destructive implementation of this automorphism acting on S-expressions:) (define (*A123498! s) (cond ((null? s) s) ((and (pair? (cdr s)) (pair? (cadr s))) (let ((old-cddr-s (cddr s))) (set-cdr! (cdr s) (cdadr s)) (set-cdr! (cadr s) old-cddr-s)) (*A074679! s)) ((pair? (cdr s)) (*A072796! s)) ((pair? (car s)) (*A072797! s))) s)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 11 2006
STATUS
approved