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

a(n) = (13-(-1)^n)/2 - 6*(C(2*(n-1),(n-1)) mod 2) - 3*(C(n^2,n+2) mod 2) - 3*(C((n-1)^2,n+1) mod 2), with n>=1. - Paolo P. Lava, Feb 01 2008

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

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Last modified October 14 14:39 EDT 2019. Contains 328019 sequences. (Running on oeis4.)