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A330940 a(n) is the least value whose binary representation can be obtained by interleaving (or shuffling) two copies of the binary representation of n. 3

%I #16 Apr 22 2020 19:23:26

%S 0,3,10,15,36,43,54,63,136,147,170,175,204,219,238,255,528,547,586,

%T 591,660,683,694,703,792,819,858,879,924,955,990,1023,2080,2115,2186,

%U 2191,2340,2347,2358,2367,2600,2643,2730,2735,2764,2779,2798,2815,3120,3171

%N a(n) is the least value whose binary representation can be obtained by interleaving (or shuffling) two copies of the binary representation of n.

%C The binary representation of all positive terms are square binary words (see A191755).

%H Rémy Sigrist, <a href="/A330940/b330940.txt">Table of n, a(n) for n = 0..8192</a>

%H Rémy Sigrist, <a href="/A330940/a330940.png">Logarithmic scatterplot of the first difference of the first 2^13 terms</a>

%H Rémy Sigrist, <a href="/A330940/a330940.gp.txt">PARI program for A330940</a>

%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>

%F a(2^k) = 2^k*(1+2^(k+1)) = A007582(k+1) for any k >= 0.

%F a(2^k-1) = 4^k-1 = A024036(k) for any k >= 0.

%F a(n) <= A330941(n).

%e The first terms, alongside the binary representation of n and of a(n), are:

%e n a(n) bin(n) bin(a(n))

%e -- ---- ------ ---------

%e 0 0 0 0

%e 1 3 1 11

%e 2 10 10 1010

%e 3 15 11 1111

%e 4 36 100 100100

%e 5 43 101 101011

%e 6 54 110 110110

%e 7 63 111 111111

%e 8 136 1000 10001000

%e 9 147 1001 10010011

%e 10 170 1010 10101010

%e 11 175 1011 10101111

%o (PARI) See Links section.

%Y See A330941 for the maximum variant.

%Y Cf. A007582, A024036, A191755, A193020.

%K nonn,base

%O 0,2

%A _Rémy Sigrist_, Jan 04 2020

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Last modified April 24 00:30 EDT 2024. Contains 371917 sequences. (Running on oeis4.)