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A151783 a(n) = 4^(wt(n) - 1) where wt(n) = A000120(n). 4

%I #17 Nov 17 2022 05:27:01

%S 1,1,4,1,4,4,16,1,4,4,16,4,16,16,64,1,4,4,16,4,16,16,64,4,16,16,64,16,

%T 64,64,256,1,4,4,16,4,16,16,64,4,16,16,64,16,64,64,256,4,16,16,64,16,

%U 64,64,256,16,64,64,256,64,256,256,1024,1,4,4,16,4,16,16,64,4,16,16,64,16,64

%N a(n) = 4^(wt(n) - 1) where wt(n) = A000120(n).

%e From _Omar E. Pol_, Jul 21 2009: (Start)

%e If written as a triangle:

%e 1;

%e 1,4;

%e 1,4,4,16;

%e 1,4,4,16,4,16,16,64;

%e 1,4,4,16,4,16,16,64,4,16,16,64,16,64,64,256;

%e 1,4,4,16,4,16,16,64,4,16,16,64,16,64,64,256,4,16,16,64,16,64,64,256,16,64,...

%e (End)

%o (Python 3.10+)

%o def A151783(n): return 1<<(n.bit_count()-1<<1) # _Chai Wah Wu_, Nov 15 2022

%Y Cf. A000120, A048881, A048896, A147610, A151780.

%Y Cf. A000302, A102376. [_Omar E. Pol_, Jul 21 2009]

%Y A102376 is a very similar sequence.

%K nonn

%O 1,3

%A _N. J. A. Sloane_, Jun 25 2009

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)