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A258201
a(n) = smallest number encountered when iterating the map x -> floor(tan(x)) starting from the initial value x = n.
5
0, 1, -3, -3, 1, -4, -3, 0, -7, -3, 0, -226, -3, 0, 0, -3, 0, -3, -3, 0, -3, -3, 0, 1, -3, -3, 1, -4, -3, 0, -7, -3, 0, -76, -3, 0, 0, -3, 0, -3, -3, 0, -3, -3, 0, 1, -3, -3, 1, -4, -3, 0, -7, -3, 0, -46, -3, 0, -7, -3, 0, -3, -3, 0, -3, -3, 0, 1, -3, -3, 1, -4, -3, 0, -6, -3, 0, -33, -3, 0
OFFSET
0,3
COMMENTS
Note that this sequence lists such values only for nonnegative integers, although the function is defined in all Z.
LINKS
FORMULA
If n is equal to floor(tan(n)) then a(n) = n, otherwise (for any other n whether positive or negative) a(n) = min(n, a(floor(tan(n))). [Recurrence defined in whole Z.]
PROG
(MIT/GNU Scheme) (define (A258201 n) (let loop ((n n) (m n)) (let ((next (floor->exact (tan n)))) (if (= n next) m (loop next (min m next))))))
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, May 26 2015
STATUS
approved