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

2,2

Comments

Sum of all terms gives 365.

Links

Table of n, a(n) for n=2..43.

Example

For n=4 three dates (1st of March, 2nd of February, 3rd of January) sum to n, so a(4) = 3.

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

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 *)

Prog

(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]

Crossrefs

Cf. A008685.

Sequence in context: A327886 A331166 A304232 * A357030 A303219 A071523

Adjacent sequences: A377290 A377291 A377292 * A377294 A377295 A377296

Keyword

nonn,dumb,easy,fini,full

Author

Manuel Biwer, Dec 27 2024

Status

approved