A258201 a(n) = smallest number encountered when iterating the map x -> floor(tan(x)) starting from the initial value x = n.

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

Antti Karttunen, Table of n, a(n) for n = 0..10000

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

Cf. A000503, A258020, A258021, A258022, A258024, A258202.

Sequence in context: A137876 A016604 A255058 * A164731 A226576 A297902

Adjacent sequences: A258198 A258199 A258200 * A258202 A258203 A258204

Keyword

sign

Author

Antti Karttunen, May 26 2015

Status

approved