A103508 a(n) = 1 + 2 * least i such that A103507(i)=n+1, 0 if no such i exists.

9, 15, 31, 101, 139, 227, 91, 503, 995, 451, 751, 539, 1819, 1397, 2957, 3461, 1831, 1417, 6023, 3769, 1777, 9587, 5411, 9421, 18653, 8089, 4511, 6541, 10529, 16051, 19049, 13163, 3139, 22937, 23929, 43363, 24919, 43571, 97367, 55571, 14419, 75209

Offset: 1

Author

Lei Zhou, Feb 10 2005

Keywords

• nonn
• hard

Crossrefs

Cf. A103510, A103151, A103152, A103153, A103506, A103507, A025017.

Programs

Scheme

(define (A103508 n) (+ 1 (* 2 (first-n-where-fun_n-is-i1 A103507 (+ 1 n)))))
(define (first-n-where-fun_n-is-i1 fun i) (let loop ((n 1)) (cond ((= i (fun n)) n) (else (loop (+ n 1))))))

Extensions

Edited and Scheme-code added by Antti Karttunen, Jun 19 2007