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Partial sums of A002487.
0

%I #5 Mar 30 2012 18:41:14

%S 1,3,4,7,9,12,13,17,20,25,27,32,35,39,40,45,49,56,59,67,72,79,81,88,

%T 93,101,104,111,115,120,121,127,132,141,145,156,163,173,176,187,195,

%U 208,213,225,232,241,243,252,259,271,276,289,297,308,311,321,328,339,343,352,357

%N Partial sums of A002487.

%F a(2n) = a(n-2)+2a(n-1)+2, a(2n+1) = 2a(n-1)+a(n)+2. - _Ralf Stephan_, Oct 08 2003

%o (PARI) a(n)=if(n<2,if(n<1,1,3),if(n%2==0,if(n==2,4,a(n/2-2)+2*a(n/2-1)+2),2*a((n-3)/2)+a((n-1)/2)+2))

%K nonn

%O 0,2

%A _N. J. A. Sloane_, May 24 2002