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A076376
Numbers k such that k, 2*k and 4*k are balanced numbers (A020492).
3
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
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 15 2002
STATUS
approved