A140259 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A140259

a(0)=3; a(n)=A002264(n+11) if a(n-1)=1, a(n) = a(n-1)-1 if (n-1) mod 3 <> 0, otherwise a(n-1).

3, 3, 2, 1, 5, 4, 3, 3, 2, 1, 7, 6, 5, 5, 4, 3, 3, 2, 1, 10, 9, 8, 8, 7, 6, 6, 5, 4, 4, 3, 2, 2, 1, 14, 14, 13, 12, 12, 11, 10, 10, 9, 8, 8, 7, 6, 6, 5, 4, 4, 3, 2, 2, 1, 21, 21, 20, 19, 19, 18, 17, 17, 16, 15, 15, 14, 13, 13, 12, 11, 11, 10, 9, 9, 8, 7, 7, 6, 5, 5, 4, 3, 3, 2, 1, 32, 31

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

COMMENTS

Position of the knot after each iteration in Werneck's Black Pearl Necklace problem.

LINKS

Table of n, a(n) for n=0..86.

Nicolau Werneck, Adaptoide, a library for adaptive finite automata. Source code in C++ available.

Nicolau Werneck, The Black Pearl Necklace, description of the problem.

Nicolau Werneck, et al. Discussion on the NKS Forum

PROG

(Scheme:) (define (A140259 n) (cond ((zero? n) 3) ((= 1 (A140259 (- n 1))) (A002264 (+ n 11))) ((not (zero? (modulo (- n 1) 3))) (- (A140259 (- n 1)) 1)) (else (A140259 (- n 1)))))

CROSSREFS

Cf. A134342, A140260, A140261.

Sequence in context: A038766 A080993 A377787 * A175644 A102905 A020862

Adjacent sequences: A140256 A140257 A140258 * A140260 A140261 A140262

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 16 2008, based on the 2008 postings by Nicolau Leal Werneck (nwerneck(AT)gmail.com).

STATUS

approved