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A272681
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Smallest binary square that begins with the binary expansion of n.
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3
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0, 1, 100, 11001, 100, 1010001, 11001, 1111001, 10000, 1001, 1010001, 101101001, 11001, 110111001, 11100001, 1111001, 10000, 10001000001, 100100, 1001110001, 1010001, 10101001, 101101001, 10111110001, 110001, 11001, 1101001001, 110111001, 11100001, 111010001001
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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REFERENCES
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Allan C. Wechsler, posting to math-fun mailing list May 22 2016.
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LINKS
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EXAMPLE
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a(10)=1010001 = 81_10, because 1010001_2 begins with 1010 = 10_2.
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PROG
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(Python)
from gmpy2 import isqrt
if n == 0:
return 0
else:
d, nd = 1, n
while True:
x = (isqrt(nd-1)+1)**2
if x < nd+d:
return int(bin(x)[2:])
d *= 2
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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