A304085 - OEIS

%I #6 May 12 2018 14:44:39

%S 1,2,6,3,24,12,4,8,120,60,20,5,40,10,30,15,840,420,140,35,7,280,70,14,

%T 210,105,21,168,84,28,56,7560,42,1890,945,315,63,9,3780,1260,252,36,

%U 2520,630,126,18,1512,756,189,27,378,54,1080,540,180,45,360,90,270,135,83160,504,72,216,108,41580,13860,3465,693,99,11,27720,6930,1386,198,22,20790

%N Divisor-or-multiple permutation of natural numbers: a(n) = A052330(A304083(n)).

%C Each a(n) is always either a divisor or a multiple of a(n+1).

%H Antti Karttunen, <a href="/A304085/b304085.txt">Table of n, a(n) for n = 0..16383</a>

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

%F a(n) = A052330(A304083(n)).

%o (PARI)

%o up_to_e = 16; \\ Good for computing up to n = (2^16)-1

%o v050376 = vector(up_to_e);

%o ispow2(n) = (n && !bitand(n,n-1));

%o i = 0; for(n=1,oo,if(ispow2(isprimepower(n)), i++; v050376[i] = n); if(i == up_to_e,break));

%o A050376(n) = v050376[n];

%o A052330(n) = { my(p=1,i=1); while(n>0, if(n%2, p *= A050376(i)); i++; n >>= 1); (p); };

%o A304085(n) = A052330(A304083(n)); \\ Needs also code from A304083

%Y Cf. A304086 (inverse).

%Y Cf. A304083, A304087.

%Y Cf. also A064736, A113552, A207901, A281978, A282291, A302350, A302781, A302783, A303751, A303771 for similar permutations.

%K nonn

%O 0,2

%A _Antti Karttunen_, May 06 2018