Lengths of months in the Gregorian calendar.

Terms

a(0) =31a(1) =28a(2) =31a(3) =30a(4) =31a(5) =30a(6) =31a(7) =31a(8) =30a(9) =31a(10) =30a(11) =31a(12) =31a(13) =28a(14) =31a(15) =30a(16) =31a(17) =30a(18) =31a(19) =31a(20) =30a(21) =31a(22) =30a(23) =31a(24) =31a(25) =28a(26) =31a(27) =30a(28) =31a(29) =30