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
Examples
a(7) = 6 because (7 + 5)/2 = 6.
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).
Programs
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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 *)
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).
Extensions
More terms from Stefan Steinerberger, May 26 2007