A377293 Number of days where month plus day equals n, in a non-leap year in the Gregorian calendar.
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 11, 11, 10, 10, 8, 8, 6, 6, 5, 3, 3, 1, 1
Offset: 2
Examples
For n=4 three dates (1st of March, 2nd of February, 3rd of January) sum to n, so a(4) = 3.
Crossrefs
Cf. A008685.
Programs
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Maple
(p-> add(coeff(p, x, i), i=2..degree(p)))(add(add(x^(i+j), j=1.. [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][i]), i=1..12)); # Alois P. Heinz, Dec 27 2024
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Mathematica
dON[d_]:=With[{d1=Take[DateList[d],3]},d1[[2]]+d1[[3]]]; Tally[dON/@DateRange[{2025,1,1},{2025,12,31}]][[;;,2]] (* Harvey P. Dale, Feb 16 2025 *) -
Python
sequence = [] for year in range(2, 43): current_count = 0 for month, days_in_month in zip(range(1, 13), (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31)): for day in range(1, days_in_month + 1): if month + day == year: current_count += 1 sequence += [current_count]
Comments