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Search: id:A108322
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| A108322 |
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"Binary prime squares": perfect squares n^2 written in base 2 which, considered as decimal numbers, are primes; 0 if no such "binary prime square" exists. |
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2
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| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1101001001, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10111110001, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 101000101001, 0, 101011111001, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1000110001001, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; listen)
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OFFSET
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0,29
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COMMENT
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Another definition: numbers having only digits 1 and 0, which, read in base 10 are primes and in base 2 are perfect squares.
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EXAMPLE
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a(5)=0 because 5^2=25(b10)=11001(b2), which read as the decimal number 11,001 is not prime.
a(29)=1101001001 because 29^2=841(b10)=1101001001, which read as the decimal 1101001001 is prime.
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CROSSREFS
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Sequence in context: A122971 A139571 A134595 this_sequence A108323 A154474 A096553
Adjacent sequences: A108319 A108320 A108321 this_sequence A108323 A108324 A108325
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KEYWORD
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easy,nonn
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AUTHOR
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Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), Jun 30 2005
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