Oblong numbers k for which phi(k) is also an oblong number.

Terms

a(0) =6a(1) =42a(2) =182a(3) =650a(4) =930a(5) =4830a(6) =7482a(7) =9506a(8) =12882a(9) =13572a(10) =16770a(11) =79242a(12) =167690a(13) =181902a(14) =228006a(15) =289982a(16) =380072a(17) =3480090a(18) =5209806a(19) =6872262a(20) =10102862a(21) =16068072a(22) =56002772a(23) =56648202a(24) =59174556a(25) =70299840a(26) =74831150a(27) =123287712a(28) =261517412a(29) =342601590