Number of von Neumann regular elements in the ring of 2 X 2 matrices over Z_n.

Terms

a(0) =1a(1) =16a(2) =81a(3) =169a(4) =625a(5) =1296a(6) =2401a(7) =2113a(8) =4753a(9) =10000a(10) =14641a(11) =13689a(12) =28561a(13) =38416a(14) =50625a(15) =29185a(16) =83521a(17) =76048a(18) =130321a(19) =105625a(20) =194481a(21) =234256a(22) =279841a(23) =171153a(24) =318001a(25) =456976a(26) =338257a(27) =405769a(28) =707281a(29) =810000