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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.
2
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.
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
Sequence in context: A354434 A362842 A338059 * A331525 A057063 A108236
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 20 2015
STATUS
approved