A260430 Involution of natural numbers: a(1) = 1, a(A257803(1+n)) = A257804(a(n)), a(A257804(n)) = A257803(1+a(n)), where A257803 and A257804 give the positions of odd and even terms in A233271, the infinite trunk of inverted binary beanstalk.

1, 4, 12, 2, 30, 7, 6, 74, 19, 21, 18, 3, 172, 52, 54, 49, 48, 11, 9, 383, 10, 128, 125, 32, 36, 132, 31, 119, 118, 5, 27, 24, 812, 314, 89, 25, 283, 92, 275, 76, 86, 85, 83, 290, 75, 267, 266, 17, 16, 68, 60, 14, 724, 15, 227, 1675, 219, 659, 207, 51, 64, 599, 216, 61, 232, 583, 174, 50, 204, 210, 201, 193, 208, 8, 45, 40, 1574, 612, 173, 569, 595, 159, 43

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..4453

Index entries for sequences that are permutations of the natural numbers

Formula

a(1) = 1; for n > 1, if A257800(n) = 0 [when n is one of the terms of A257804] a(n) = A257803(1+a(A257808(n))), otherwise [when n is one of the terms of A257803] a(n) = A257804(a(A257807(n)-1)).

Prog

(Scheme, with memoizing macro definec)
(definec (A260430 n) (cond ((<= n 1) n) ((zero? (A257800 n)) (A257803 (+ 1 (A260430 (A257808 n))))) (else (A257804 (A260430 (+ -1 (A257807 n)))))))

Crossrefs

Cf. A257800, A257803, A257804, A257807, A257808.

Cf. also A233271, A257806.

Related permutations: A260431 - A260434.

Sequence in context: A016487 A370707 A104063 * A243347 A317555 A213343

Adjacent sequences: A260427 A260428 A260429 * A260431 A260432 A260433

Keyword

nonn

Author

Antti Karttunen, Jul 27 2015

Status

approved