Numbers k such that phi(k) = Sum_{d|k} core(d) where core(x) is the squarefree part of x (A007913).

Terms

a(0) =1a(1) =99a(2) =1080a(3) =1836a(4) =4743a(5) =5670a(6) =7644a(7) =8307a(8) =14384a(9) =14784a(10) =15225a(11) =15824a(12) =16065a(13) =20300a(14) =21584a(15) =25704a(16) =29760a(17) =34544a(18) =46816a(19) =71568a(20) =94240a(21) =128412a(22) =169290a(23) =264160a(24) =266266a(25) =312480a(26) =331731a(27) =364941a(28) =404550a(29) =445050