Square numbers n such that sigma(n) is a triangular number.

Terms

a(0) =1a(1) =36a(2) =441a(3) =5625a(4) =6084a(5) =407044a(6) =8444836a(7) =17388900a(8) =35070084a(9) =40729924a(10) =57790404a(11) =80138304a(12) =537822481a(13) =588159504a(14) =659821969a(15) =918999225a(16) =1820387556a(17) =2179862721a(18) =2599062361a(19) =5110963081a(20) =28816420516a(21) =36144473689a(22) =46082779561a(23) =55145598561a(24) =147225690000a(25) =163405126756