A231011 Number of months after which a date can fall on the same day of the week, and the two months can have the same number of days, in the Julian calendar.

0, 3, 6, 8, 9, 14, 15, 17, 18, 20, 22, 23, 26, 29, 31, 32, 34, 35, 37, 38, 40, 43, 46, 52, 54, 55, 57, 60, 63, 64, 68, 69, 72, 75, 77, 78, 80, 81, 86, 89, 92, 94, 95, 98, 101, 103, 106, 109, 110, 112, 114, 115, 117, 118, 123, 124, 126, 127, 129, 132, 135, 140, 141, 147, 149, 150

Offset

0,2

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 a subsequence of A231010.

Links

Table of n, a(n) for n=0..65.

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

Crossrefs

Cf. A230995-A231014.

Cf. A231006 (Gregorian calendar).

Sequence in context: A140516 A310140 A231006 * A196370 A005622 A072960

Adjacent sequences: A231008 A231009 A231010 * A231012 A231013 A231014

Keyword

nonn,easy

Author

Aswini Vaidyanathan, Nov 02 2013

Status

approved