A153883 a(n) = A153880(n)/2.

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, 61, 63, 64, 66, 67, 72, 73, 75, 76, 78, 79, 84, 85, 87, 88, 90, 91, 96, 97, 99, 100, 102, 103, 120, 121, 123, 124, 126, 127, 132, 133, 135, 136, 138, 139, 144, 145, 147, 148

Offset: 0

Author

Antti Karttunen, Jan 03 2009

Keywords

• base
• nonn

Crossrefs

Cf. A153880.

Programs

Scheme

; MIT Scheme
(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)))))))