Westminster chimes at 15-minute intervals (2).

Terms

a(0) =4a(1) =8a(2) =12a(3) =17a(4) =4a(5) =8a(6) =12a(7) =18a(8) =4a(9) =8a(10) =12a(11) =19a(12) =4a(13) =8a(14) =12a(15) =20a(16) =4a(17) =8a(18) =12a(19) =21a(20) =4a(21) =8a(22) =12a(23) =22a(24) =4a(25) =8a(26) =12a(27) =23a(28) =4a(29) =8