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A231010
Number of months after which a date can fall on the same day of the week, in the Julian calendar.
5
0, 1, 3, 6, 8, 9, 11, 14, 15, 17, 18, 19, 20, 22, 23, 26, 27, 28, 29, 31, 32, 34, 35, 37, 38, 40, 41, 43, 45, 46, 49, 52, 54, 55, 57, 58, 60, 61, 63, 64, 66, 68, 69, 71, 72, 73, 74, 75, 77, 78, 80, 81, 83, 86, 87, 89, 91, 92, 94, 95, 98, 100, 101, 103, 104, 106, 109, 110, 112
OFFSET
0,3
COMMENTS
In the Julian calendar, a year is a leap year if and only if it is a multiple of 4 and all century years are leap years.
Assuming this fact, this sequence is periodic with a period of 336.
LINKS
PROG
(PARI) m=[0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5]; n=[31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]; y=vector(336, i, (m[((i-1)%12)+1]+((5*((i-1)\48)+(((i-1)\12)%4)-!((i-1)%48)-!((i-2)%48))))%7); x=vector(336, i, n[((i-1)%12)+1]+!((i-2)%48)); for(p=0, 336, for(q=0, 336, if(y[(q%336)+1]==y[((q+p)%336)+1], print1(p", "); break)))
CROSSREFS
Cf. A231005 (Gregorian calendar).
Sequence in context: A186385 A335155 A231005 * A285250 A188469 A005652
KEYWORD
nonn,easy
AUTHOR
Aswini Vaidyanathan, Nov 02 2013
STATUS
approved