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A015800
Numbers k such that phi(k) + 9 | sigma(k).
1
26, 312, 828, 2475, 2520, 4950, 7412, 7942, 10464, 14454, 30952, 89262, 1029632, 3116544, 17721152, 56889152, 538655552, 804839424, 9287924224, 206150959104, 698155922432
OFFSET
1,1
COMMENTS
a(22) > 10^12. - Donovan Johnson, Feb 28 2012
MATHEMATICA
Cases[Range[100000],
x_ /; Divisible[DivisorSigma[1, x], EulerPhi[x] + 9] == True] (* David Nacin, Feb 28 2012 *)
Select[Range[1000000], Divisible[DivisorSigma[1, #], EulerPhi[#]+9]&] (* Harvey P. Dale, May 24 2012 *)
CROSSREFS
Sequence in context: A000498 A066912 A359622 * A276285 A232064 A030647
KEYWORD
nonn
EXTENSIONS
a(9)-a(21) from Donovan Johnson, Feb 28 2012
STATUS
approved