A273671 Permutation of natural numbers: a(n) = A270436(A007305(n+1)) * A270437(A047679(n-1)).

1, 8, 2, 27, 54, 24, 3, 64, 250, 375, 192, 108, 135, 40, 4, 125, 686, 96, 1029, 1372, 160, 1715, 500, 320, 875, 16000, 448, 189, 3456, 56, 5, 216, 1458, 3993, 3000, 5324, 10985, 8640, 2916, 3645, 12096, 281216, 9317, 7000, 170368, 5103, 1080, 750, 3087, 352, 3430, 3773, 416, 4116, 1125, 576, 1500, 1625, 704, 270, 297, 72, 6, 343

Offset: 1

Author

Antti Karttunen, May 27 2016

Keywords

• nonn
• look

Comments

Permutation of natural numbers induced by looking up the position of A007305(n+1)/A047679(n-1) [each fraction in the full Stern-Brocot tree] in the set of positive rationals as ordered by A270418(n)/A270419(n).

Links

• Antti Karttunen, Table of n, a(n) for n = 1..8192
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Inverse: A273672.

Cf. A007305, A047679, A270418, A270419, A270436, A270437.

Programs

Scheme

(define (A273671 n) (* (A270436 (A007305 (+ 1 n))) (A270437 (A047679 (- n 1)))))

Formula

a(n) = A270436(A007305(n+1)) * A270437(A047679(n-1)).