%I #11 May 05 2023 18:12:13

%S 0,1,3,4,6,7,12,13,15,16,18,19,24,25,27,28,30,31,36,37,39,40,42,43,60,

%T 61,63,64,66,67,72,73,75,76,78,79,84,85,87,88,90,91,96,97,99,100,102,

%U 103,120,121,123,124,126,127,132,133,135,136,138,139,144,145,147,148

%N a(n) = A153880(n)/2.

%o (Scheme)

%o ; MIT Scheme

%o (define (A153883 n) (let loop ((n n) (z 0) (i 2) (f 1)) (cond ((zero? n) z) (else (loop (floor->exact (/ n i)) (+ (* f (modulo n i)) z) (1+ i) (* f (+ i 1)))))))

%Y Cf. A153880.

%K base,nonn

%O 0,3

%A _Antti Karttunen_, Jan 03 2009