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Search: id:A069118
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| A069118 |
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Let D(n,s) denotes the denominator of sum(k=1,n,1/k^s); sequence gives values of n such that D(n,4)/D(n,2) is a perfect square. |
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1
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| 1, 2, 3, 4, 5, 6, 7, 8, 9, 15, 16, 17, 18, 19, 28, 29, 30, 31, 32, 33, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144
(list; graph; listen)
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OFFSET
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1,2
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PROGRAM
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(PARI) precision 1000 digits : for(n=1, 300, if(sqrt(denominator(sum(i=1, n, 1/i^4))/denominator(sum(i=1, n, 1/i^2))) == floor(sqrt(denominator(sum(i=1, n, 1/i^4))/denominator(sum(i=1, n, 1/i^2)))), print1(n, ", ")))
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CROSSREFS
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Sequence in context: A151543 A073526 A032992 this_sequence A032978 A049101 A048406
Adjacent sequences: A069115 A069116 A069117 this_sequence A069119 A069120 A069121
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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), Apr 07 2002
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