A231013 Number of months after which it is not possible to have a date falling on the same day of the week, in the Julian calendar.

2, 4, 5, 7, 10, 12, 13, 16, 21, 24, 25, 30, 33, 36, 39, 42, 44, 47, 48, 50, 51, 53, 56, 59, 62, 65, 67, 70, 76, 79, 82, 84, 85, 88, 90, 93, 96, 97, 99, 102, 105, 107, 108, 111, 116, 119, 120, 122, 125, 128, 134, 136, 137, 139, 142, 144, 145, 148, 151, 153, 154, 156, 157, 162

Offset

1,1

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.

This is the complement of A231010.

Links

Table of n, a(n) for n=1..64.

Time And Date, Repeating Months

Time And Date, Julian Calendar

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, j=0; for(q=0, 336, if(y[(q%336)+1]==y[((q+p)%336)+1], j=1; break)); if(j==0, print1(p", ")))

Crossrefs

Cf. A230995-A231014.

Cf. A231008 (Gregorian calendar).

Sequence in context: A364132 A285251 A325124 * A231008 A092311 A335365

Adjacent sequences: A231010 A231011 A231012 * A231014 A231015 A231016

Keyword

nonn,easy

Author

Aswini Vaidyanathan, Nov 02 2013

Status

approved