Numbers k such that phi(k+1) - phi(k) = k/2.

Terms

a(0) =2a(1) =4a(2) =16a(3) =24a(4) =216a(5) =256a(6) =4960a(7) =10648a(8) =65536a(9) =195112a(10) =1191016a(11) =7544800a(12) =11530464a(13) =12705504a(14) =45882712a(15) =55742968a(16) =179883264a(17) =946966168a(18) =2106997768a(19) =2289529432a(20) =2548895896a(21) =3056745600a(22) =3482123272a(23) =7756683264a(24) =10735357816a(25) =15920801280a(26) =26946035992a(27) =46827274240