Numbers n such that n = concatenate(a, b) and sigma(a) + sigma(b) = phi(n).

Terms

a(0) =12a(1) =420a(2) =966a(3) =2700a(4) =5700a(5) =5940a(6) =7440a(7) =12540a(8) =71100a(9) =76680a(10) =107880a(11) =118680a(12) =121920a(13) =156420a(14) =160650a(15) =161880a(16) =259080a(17) =284580a(18) =339150a(19) =353430a(20) =395850a(21) =498420a(22) =585200a(23) =600780a(24) =701220a(25) =746130a(26) =752100a(27) =771420a(28) =870870a(29) =1052220