A129000 Start with an integer (in this case, 1). First, add 5 or 8 if the integer is odd or even, respectively. Then divide by 2.

1, 3, 4, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..1001

Tanya Khovanova, Arithmetic Progressions

Index entries for linear recurrences with constant coefficients, signature (0, 1).

Formula

a(n) = (a(n-1) + b)/d, if a(n) even = (a(n-1) + c)/d, if a(n) odd (starting with a(1)=1, b=5, c=8, d=2).

Example

a(7) = 6 because (7 + 5)/2 = 6.

Mathematica

a={1}; k=1; For[n=1, n<70, n++, If[EvenQ[k], k=k+8, k=k+5]; k=k/2; AppendTo[a, k]]; a (* Stefan Steinerberger, May 26 2007 *)

Prog

(Scheme, with memoization-macro definec) (definec (A129000 n) (if (= 1 n) n (let ((prev (A129000 (- n 1)))) (/ (+ prev (if (odd? prev) 5 8)) 2)))) ;; Antti Karttunen, Sep 14 2017

Crossrefs

Cf. A081742, A089610, A014499, A071673.

Sequence in context: A135599 A283740 A167161 * A260158 A317093 A181590

Adjacent sequences: A128997 A128998 A128999 * A129001 A129002 A129003

Keyword

easy,nonn

Author

Adam F. Schwartz (adam_s(AT)mit.edu), May 01 2007

Extensions

More terms from Stefan Steinerberger, May 26 2007

Status

approved