The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #7 Jan 11 2019 04:23:32
%S 11398670,22797340,38369450,45594680,56993350,59334310,76738900,
%T 91189360,113986700,118668620,153477800,182378720,209524210,227973400,
%U 237337240,268586150,284966750,306955600,364757440,419048420,455946800,474674480,537172300,539867650,569933500
%N Smallest member of sociable quadruples using Dedekind psi function (A001615).
%C Numbers k whose iterations of k -> A001615(k) - k are cyclic with a period of 4, and in each cyclic quadruple k is the least of the 4 members.
%e 11398670 is in the sequence since the iterations of k -> A001615(k) - k are cyclic with a period of 4: 11398670, 11475730, 12474350, 14093650, 11398670, ... and 11398670 is the smallest member of the quadruple.
%t t[0]=0; t[1]=0; t[n_]:=(Times@@(1+1/Transpose[FactorInteger[n]][[1]])-1)*n;
%t seq[n_]:=NestList [t, n, 4][[2;; 5]] ; aQ[n_] := Module[ {s=seq[n]}, n==Min[s] && Count[s, n]==1]; s={}; Do[If[aQ[n], AppendTo[s, n]], {n, 1, 10^9}]; s
%Y Cf. A001615, A090615, A319902, A319915, A323327, A323328, A323329, A323330.
%K nonn
%O 1,1
%A _Amiram Eldar_, Jan 11 2019