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A151783
a(n) = 4^(wt(n) - 1) where wt(n) = A000120(n).
4
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, 64, 64, 256, 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, 64, 256, 64, 256, 256, 1024, 1, 4, 4, 16, 4, 16, 16, 64, 4, 16, 16, 64, 16, 64
OFFSET
1,3
EXAMPLE
From Omar E. Pol, Jul 21 2009: (Start)
If written as a triangle:
1;
1,4;
1,4,4,16;
1,4,4,16,4,16,16,64;
1,4,4,16,4,16,16,64,4,16,16,64,16,64,64,256;
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,...
(End)
PROG
(Python 3.10+)
def A151783(n): return 1<<(n.bit_count()-1<<1) # Chai Wah Wu, Nov 15 2022
CROSSREFS
Cf. A000302, A102376. [Omar E. Pol, Jul 21 2009]
A102376 is a very similar sequence.
Sequence in context: A350639 A347264 A328147 * A258853 A275791 A093561
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 25 2009
STATUS
approved