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Search: id:A071011
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| A071011 |
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Numbers n such that n is a sum of 2 squares (i.e. n is in A001481(k)) and sigma(n)==0 mod 4. |
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1
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| 65, 85, 125, 130, 145, 170, 185, 205, 221, 250, 260, 265, 290, 305, 340, 365, 370, 377, 410, 442, 445, 481, 485, 493, 500, 505, 520, 530, 533, 545, 565, 580, 585, 610, 629, 680, 685, 689, 697, 730, 740, 745, 754, 765, 785, 793, 820, 865, 884, 890, 901, 905
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It is conjectured that if m is not a sum of 2 squares (i.e. m is in A022544(k)) sigma(m)==0 mod 4
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PROGRAM
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(PARI) for(n=1, 1000, if(1-sign(sum(i=0, n, sum(j=0, i, if(i^2+j^2-n, 0, 1))))+sigma(n)%4==0, print1(n, ", ")))
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CROSSREFS
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Cf. A001481, A022544.
Sequence in context: A025312 A024508 A025303 this_sequence A084648 A024409 A131574
Adjacent sequences: A071008 A071009 A071010 this_sequence A071012 A071013 A071014
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), May 19 2002
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