A033171 Number of days in n years (n=4 is the first leap year).
365, 730, 1095, 1461, 1826, 2191, 2556, 2922, 3287, 3652, 4017, 4383, 4748, 5113, 5478, 5844, 6209, 6574, 6939, 7305, 7670, 8035, 8400, 8766, 9131, 9496, 9861, 10227, 10592, 10957, 11322, 11688, 12053, 12418, 12783, 13149, 13514, 13879
Offset: 1
Formula
From Chai Wah Wu, Jan 25 2020: (Start)
As the beginning year is not specified, the sequence is only well-defined if we ignore the rule where if a year is divisible by 100 but not by 400, it is not a leap year. Assuming that, we have the following formulas:
a(n) = a(n-1) + a(n-4) - a(n-5) for n > 5.
G.f.: x*(366*x^3 + 365*x^2 + 365*x + 365)/(x^5 - x^4 - x + 1). (End)