A076182 a(n) = A006666(n) mod 2.

0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,1

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Index entries for sequences related to 3x+1 (or Collatz) problem

Index entries for characteristic functions

Formula

a(n) = A006513(n) - 1.

Apparently also the antiparity of A064433. - Ralf Stephan, Nov 16 2004

Prog

(PARI) a(n)=if(n<0, 0, s=n; c=0; while(s>1, s=(s%2)*(3*s+1)/2+(1-s%2)*s/2; c++); c)%2
(Scheme)
(define (A076182 n) (modulo (A006666 n) 2))
(definec (A006666 n) (if (= 1 n) 0 (+ 1 (A006666 (A014682 n))))) ;; With memoization-macro definec
(define (A014682 n) (if (even? n) (/ n 2) (/ (+ n n n 1) 2)))
;; Antti Karttunen, Aug 13 2017

Crossrefs

Cf. A014682, A006513, A006666, A076092.

Sequence in context: A057212 A023959 A341334 * A010058 A140591 A189476

Adjacent sequences: A076179 A076180 A076181 * A076183 A076184 A076185

Keyword

nonn

Author

Benoit Cloitre, Nov 01 2002

Status

approved