login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A059884 Prime factorization of n encoded by recursively interleaving bits of successive prime exponents. 7

%I

%S 0,1,2,4,8,3,128,5,32,9,32768,6,2147483648,129,10,16,

%T 9223372036854775808,33,170141183460469231731687303715884105728,12,

%U 130,32769

%N Prime factorization of n encoded by recursively interleaving bits of successive prime exponents.

%C For n=2^e0*3^e1*5^e2... the alternate (i.e. 2^0,2,4...) bit positions of a(n) give e0, the alternate *remaining* bit positions (i.e. 2^1,5,9...) give e1, the *remaining* alternates (i.e. 2^3,11,19...) give e2 and so on. (Any finite vector of nonnegative integers can be uniquely encoded this way.) Every nonnegative integer appears exactly once in this sequence-despite its outlandish behavior: the next term, a(29) is 2^511 (which has 153 digits), followed by a(30)=11...

%C Inverse of sequence A059900 considered as a permutation of the nonnegative integers. - _Howard A. Landman_, Sep 25 2001

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

%e a(360)=a(2^3 * 3^2 * 5^1)=45 thus: ...0 0 0 0 0 0 1 1 -> 3 from 2^3 ...0 0 1 0 -> 2 from 3^2 ...0 1 -> 1 from 5^1 ...00000101101 == 45.

%Y Cf. A075173, A075300, A075302.

%K easy,nonn

%O 1,3

%A _Marc LeBrun_, Feb 06 2001

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 21 02:19 EST 2018. Contains 299388 sequences. (Running on oeis4.)