A258105 Inverse to sequence defined as {b(1) = 1, and for n>1: b(n) = A257906(n)}, which is conjectured to be a permutation of natural numbers.

1, 2, 4, 6, 3, 10, 5, 8, 7, 12, 14, 18, 20, 11, 9, 16, 24, 22, 13, 26, 15, 28, 19, 32, 21, 34, 30, 36, 38, 40, 17, 44, 25, 42, 23, 48, 50, 54, 27, 52, 46, 60, 29, 56, 58, 62, 33, 64, 66, 71, 35, 69, 31, 75, 37, 77, 39, 68, 41, 81, 73, 79, 45, 83, 85, 89, 43, 87, 93, 97, 49, 91, 51, 99, 55, 101, 95, 103, 53, 105, 47, 107, 61

Offset

1,2

Comments

In case the sequence b is not a permutation of natural numbers, then neither this will be and we set a(n) = -1 for those n > 1 that do not occur in A257906.

Links

Antti Karttunen, Table of n, a(n) for n = 1..7575

Index entries for sequences that are permutations of the natural numbers

Prog

(Scheme, with macro defineperm1 from Antti Karttunen's IntSeq-library)
;; Needs also code from A257906 and A257907:
(defineperm1 (A257906_with_a1_1 n) (if (= 1 n) n (A257906 n)))
(define (A258105 n) (A257906_with_a1_1 (- n))) ;; We get cached inverse-values with negative arguments, provided that A257906_with_a1_1 has been computed first far enough.

Crossrefs

Cf. A257906, A257907.

Sequence in context: A354434 A362842 A338059 * A331525 A057063 A108236

Adjacent sequences: A258102 A258103 A258104 * A258106 A258107 A258108

Keyword

nonn

Author

Antti Karttunen, May 20 2015

Status

approved