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Search: id:A124981
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| A124981 |
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Odd numbers that are not the sum of 2 squares. |
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+0
1
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| 3, 7, 11, 15, 19, 21, 23, 27, 31, 33, 35, 39, 43, 47, 51, 55, 57, 59, 63, 67, 69, 71, 75, 77, 79, 83, 87, 91, 93, 95, 99, 103, 105, 107, 111, 115, 119, 123, 127, 129, 131, 133, 135, 139, 141, 143, 147, 151, 155, 159, 161, 163, 165, 167, 171, 175, 177, 179, 183, 187
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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Equals A022544 INTERSECT A005408. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 29 2006
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EXAMPLE
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13 is not in the list because it can be written as 3^2+2^2.
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PROGRAM
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(PARI) isA022544(n)={ local(cnt=0, y2) ; for(x=0, floor(sqrt(n)), y2=n-x^2 ; if( y2>=x^2 && issquare(y2), return(0) ; ) ; ) ; return(1) ; } isA124981(n)={ return( (n%2) && isA022544(n)) ; } { for(n=1, 200, if( isA124981(n), print1(n, ", ") ; ) ; ) ; } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 29 2006
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CROSSREFS
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Cf. A022544.
Sequence in context: A003512 A079710 A145832 this_sequence A059554 A103543 A004767
Adjacent sequences: A124978 A124979 A124980 this_sequence A124982 A124983 A124984
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Nov 15 2006
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EXTENSIONS
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Corrected and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 29 2006
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