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Search: id:A115557
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| 1, 49, 121, 169, 361, 529, 841, 961, 1849, 2209, 2809, 5329, 6889, 9409, 10609, 12769, 16129, 24649, 32041, 38809, 39601, 49729, 51529, 54289, 57121, 58081, 63001, 66049, 73441, 78961, 96721, 99856, 100489, 110889, 124609, 151321, 160801
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OFFSET
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1,2
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FORMULA
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The commutator[sigma, tau] is zero, that is A076360[x]=0 and x is square number.
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EXAMPLE
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The special prime square 121 is here because it is a square number and sigma[tau(121)]=sigma(3)=4=tau(sigma[121])=tau{1+11+121)=tau(133)=4.
The first solution of with composite square root is 316^2=99856: tau(99856)=15,
sigma(15)=24 or sigma[99856]=195951=3.7.7.31.43, tau[195951]=24.
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CROSSREFS
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Cf. A000005, A000203, A076360, A076361, A062068, A062069, A115558.
Sequence in context: A044617 A090095 A084733 this_sequence A080665 A130007 A044300
Adjacent sequences: A115554 A115555 A115556 this_sequence A115558 A115559 A115560
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana1.sote.hu), Jan 25 2006
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