A064650 a(n) = floor(a(n-1)/2) + a(n-2) with a(0)=1, a(1)=2.
1, 2, 2, 3, 3, 4, 5, 6, 8, 10, 13, 16, 21, 26, 34, 43, 55, 70, 90, 115, 147, 188, 241, 308, 395, 505, 647, 828, 1061, 1358, 1740, 2228, 2854, 3655, 4681, 5995, 7678, 9834, 12595, 16131, 20660, 26461, 33890, 43406, 55593, 71202, 91194, 116799, 149593, 191595
Offset: 0
Keywords
Links
- Harry J. Smith and Reinhard Zumkeller, Table of n, a(n) for n = 0..9300, first 401 terms from Harry J. Smith
Programs
-
Haskell
a064650 n = a064650_list !! n a064650_list = 1 : 2 : zipWith (+) a064650_list (map (flip div 2) $ tail a064650_list) -- Reinhard Zumkeller, Apr 30 2015 -
Magma
[n le 2 select n else Floor(Self(n-1)/2)+Self(n-2): n in [1..50]]; // Bruno Berselli, Apr 21 2012
-
Mathematica
RecurrenceTable[{a[0] == 1, a[1] == 2, a[n] == Floor[a[n - 1]/4] + a[n - 2]}, a, {n, 49}] (* Bruno Berselli, Apr 21 2012 *) -
PARI
{ for (n=0, 400, if (n>1, a=a1\2 + a2; a2=a1; a1=a, if (n, a=a1=2, a=a2=1)); write("b064650.txt", n, " ", a) ) } \\ Harry J. Smith, Sep 21 2009
Formula
a(n) = A064651(n) + 1.
Comments