cp's OEIS Frontend

A269851 a(0) = 1, a(A087686(1+n)) = 2*a(n), a(A088359(n)) = A250469(a(n)), where A088359 and A087686 = numbers that occur only once (resp. more than once) in A004001.

%I A269851 #8 Mar 07 2016 12:31:47
%S A269851 1,2,4,3,8,9,5,6,16,21,25,7,18,15,10,12,32,45,55,49,11,42,51,35,50,27,
%T A269851 14,36,33,30,20,24,64,93,115,91,121,13,90,123,125,77,110,147,65,98,39,
%U A269851 22,84,105,85,102,87,70,100,57,54,28,72,69,66,60,40,48,128,189,235,203,187,169,17,186,267,305,217,143,230
%N A269851 a(0) = 1, a(A087686(1+n)) = 2*a(n), a(A088359(n)) = A250469(a(n)), where A088359 and A087686 = numbers that occur only once (resp. more than once) in A004001.
%C A269851 Permutation of natural numbers obtained from the sieve of Eratosthenes, combined with the permutation obtained from Hofstadter-Conway $10000 sequence (A004001). Note the indexing: Domain starts from 0, range from 1.
%H A269851 Antti Karttunen, <a href="/A269851/b269851.txt">Table of n, a(n) for n = 0..8191</a>
%H A269851 <a href="/index/Ho#Hofstadter">Index entries for Hofstadter-type sequences</a>
%H A269851 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%H A269851 <a href="/index/Si#sieve">Index entries for sequences generated by sieves</a>
%F A269851 a(0) = 1, a(1) = 2, for n > 1, if A093879(n-1) = 0 [when n is in A087686], a(n) = 2*a(n - A004001(n)), otherwise [when n is in A088359], a(n) = A250469(a(A004001(n)-1)).
%F A269851 As a composition of related permutations:
%F A269851 a(n) = A252755(A267111(n)).
%F A269851 Other identities. For all n >= 0:
%F A269851 a(2^n) = 2^(n+1).
%o A269851 (Scheme, with memoization-macro definec)
%o A269851 (definec (A269851 n) (cond ((<= n 1) (+ 1 n)) ((zero? (A093879 (- n 1))) (* 2 (A269851 (- n (A004001 n))))) (else (A250469 (A269851 (+ -1 (A004001 n)))))))
%Y A269851 Inverse: A269852.
%Y A269851 Cf. A004001, A087686, A088359, A093879, A250469.
%Y A269851 Related or similar permutations: A252755, A267111, A269855.
%K A269851 nonn
%O A269851 0,2
%A A269851 _Antti Karttunen_, Mar 07 2016