|
%I #13 Jul 21 2021 00:44:00
%S 1,2,10,12,120,4080,5280,6720,17472,137280,174720,908160,29621760,
%T 31100160,41879040,89806080,99240960,101391360,143969280,226652160,
%U 466794240,732103680,760488960,779412480,916016640,918382080,951498240,1001172480,1365450240,3151948800,9464663040
%N Unitary deficient-perfect numbers: unitary deficient numbers k such that 2*k-usigma(k) is a unitary divisor of k, where usigma is the sum of unitary divisors of k (A034448).
%C The unitary version of A271816.
%e 120 is in the sequence since 2*120 - usigma(120) = 240 - 216 = 24, and 24 is a unitary divisor of 120.
%t usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])]; aQ[n_] := Module[{d}, d=2n-usigma[n]; If[ d<=0, False, Divisible[n,d] && GCD[d, n/d] == 1 ]]; Select[Range[100000], aQ]
%Y Cf. A034448, A271816, A303357.
%K nonn
%O 1,2
%A _Amiram Eldar_, Apr 22 2018
%E a(19)-a(31) from _Giovanni Resta_, Apr 26 2018
|
