A246364 - OEIS

%I #10 Aug 27 2014 14:53:23

%S 1,2,5,3,7,11,13,4,6,9,19,14,8,12,29,10,17,31,23,16,41,71,37,44,47,39,

%T 43,42,38,30,26,59,22,34,15,85,53,58,25,130,57,151,61,311,103,69,33,

%U 365,157,111,73,226,74,106,67,370,223,56,97,341,139,122,35,133,55,86,20,145,46,49,21,659,118,36,83,419,127,191,18

%N Permutation of natural numbers: a(n) = A064216(A227413(n)).

%C After a(2) = 2, the rest of the even bisection contains only terms of A246261. However, some of the terms of A246261 are also found in the odd bisection, while terms of A246263, apart from 2, all reside in the odd bisection of this sequence.

%H Antti Karttunen, <a href="/A246364/b246364.txt">Table of n, a(n) for n = 1..4095</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%F a(n) = A064216(A227413(n)).

%o (PARI)

%o default(primelimit,(2^31)+(2^30));

%o A002808(n) = { my(k=-1); while( -n + n += -k + k=primepi(n), ); n }; \\ This function from _M. F. Hasler_

%o A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};

%o A064216(n) = A064989((2*n)-1);

%o A227413(n) = if(1==n, 1, if(!(n%2), prime(A227413(n/2)), A002808(A227413((n-1)/2))));

%o A246364(n) = A064216(A227413(n));

%o for(n=1, 4095, write("b246364.txt", n, " ", A246364(n)));

%o (Scheme) (define (A246364 n) (A064216 (A227413 n)))

%Y Inverse: A246363.

%Y Related or similar permutations: A064216, A227413, A246366, A246368.

%Y Cf. A246261, A246263.

%K nonn

%O 1,2

%A _Antti Karttunen_, Aug 26 2014