A231012 Number of months after which a date can fall on the same day of the week, but it is not possible that the two months have the same number of days, in the Julian calendar.

1, 11, 19, 27, 28, 41, 45, 49, 58, 61, 66, 71, 73, 74, 83, 87, 91, 100, 104, 113, 121, 130, 131, 133, 138, 143, 146, 159, 160, 176, 177, 190, 193, 198, 203, 205, 206, 215, 223, 232, 236, 245, 249, 253, 262, 263, 265, 270, 275, 278, 287, 291, 295, 308, 309, 317, 325, 335

Offset

1,2

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.

These are the terms of A231010 not in A231011.

Links

Table of n, a(n) for n=1..58.

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)); for(q=0, 336, if(y[(q%336)+1]==y[((q+p)%336)+1]&&x[(q%336)+1]==x[((q+p)%336)+1], j=2; break)); if(j==1, print1(p", ")))

Crossrefs

Cf. A230995-A231014.

Cf. A231007 (Gregorian calendar).

Sequence in context: A152567 A029481 A289700 * A231007 A129916 A032694

Adjacent sequences: A231009 A231010 A231011 * A231013 A231014 A231015

Keyword

nonn,easy

Author

Aswini Vaidyanathan, Nov 02 2013

Status

approved