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A083541
Values of y from solutions to sigma(x+1)*sigma(x)=y^2, where A083539(x) = y^2 is a square number.
2
24, 48, 84, 264, 288, 312, 336, 576, 960, 1152, 1440, 1440, 1440, 1440, 1680, 2100, 2160, 2688, 2640, 3360, 3024, 3360, 3360, 4320, 4320, 5376, 4032, 4464, 5040, 4788, 6048, 7392, 6720, 6840, 7644, 6300, 7440, 7560, 7020, 10080, 10080, 8064, 10080
OFFSET
1,1
LINKS
FORMULA
a(n) = sqrt(sigma(A083540(n)) * sigma(1+A083540(n))).
MATHEMATICA
Do[s=Sqrt[DivisorSigma[1, n+1]*DivisorSigma[1, n]]; If[IntegerQ[s], Print[s]], {n, 1, 5000}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, May 21 2003
STATUS
approved