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Floor(|x*sin(x)|)-perfect numbers, where f-perfect numbers for an arithmetical function f are defined in A066218.
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%I #12 Sep 26 2019 09:05:45

%S 3,6,10,34,50,91,222,364,1485,6640,18579,775698,1035507,1706366,

%T 46388515,75714802

%N Floor(|x*sin(x)|)-perfect numbers, where f-perfect numbers for an arithmetical function f are defined in A066218.

%H J. Pe, <a href="http://jlpe.tripod.com/gpn/fperfect.htm">On a Generalization of Perfect Numbers</a>, J. Rec. Math., 31(3) (2002-2003), 168-172.

%e Let f(n) = floor(|x*sin(x)|). Then f(6) = 1 = 0+1+0 = f(3)+f(2)+f(1); so 6 is a term of the sequence.

%t f[x_] := Floor[Abs[x*Sin[x]]]; Select[ Range[2, 10^4], 2 * f[ # ] == Apply[ Plus, Map[ f, Divisors[ # ] ] ] & ]

%Y Cf. A066218.

%K nonn,more

%O 1,1

%A _Joseph L. Pe_, Dec 19 2001

%E a(11)-a(16) from _Amiram Eldar_, Sep 26 2019