A076376 Numbers k such that k, 2*k and 4*k are balanced numbers (A020492).

3, 35, 105, 210, 1045, 1485, 2970, 3135, 6270, 24871, 29029, 35343, 39105, 50065, 58435, 64285, 70686, 71145, 74613, 78210, 87087, 87685, 124605, 137885, 140335, 142290, 149226, 150195, 174174, 175305, 176715, 192855, 249210, 263055, 300390, 350610, 373065

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (calculated using data from Jud McCranie, terms 1..1000 from Donovan Johnson)

Mathematica

f[x_] := DivisorSigma[1, x]/EulerPhi[x] Do[s=f[n]; s1=f[2*n]; s2=f[4*n]; If[IntegerQ[s]&&IntegerQ[s1]&&IntegerQ[s2], Print[n]], {n, 1, 1000000}]

Crossrefs

Cf. A000010, A000203, A055234, A020492, A076375.

Sequence in context: A001539 A113854 A231645 * A338787 A353619 A133710

Adjacent sequences: A076373 A076374 A076375 * A076377 A076378 A076379

Keyword

nonn

Author

Labos Elemer, Oct 15 2002

Status

approved