A083541 Values of y from solutions to sigma(x+1)*sigma(x)=y^2, where A083539(x) = y^2 is a square number.

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

Amiram Eldar, Table of n, a(n) for n = 1..10000

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

Cf. A000203, A083539, A083540, A083538, A060780, A060781.

Sequence in context: A054734 A174906 A029613 * A230761 A073763 A359750

Adjacent sequences: A083538 A083539 A083540 * A083542 A083543 A083544

Keyword

nonn

Author

Labos Elemer, May 21 2003

Status

approved