A231003 Number of years after which it is not possible to have a date falling on the same day of the week, in the Julian calendar.

1, 2, 3, 4, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 24, 25, 26, 27, 29, 30, 31, 32, 35, 36, 37, 38, 40, 41, 42, 43, 44, 46, 47, 48, 49, 52, 53, 54, 55, 57, 58, 59, 60, 63, 64, 65, 66, 68, 69, 70, 71, 72, 74, 75, 76, 77, 80, 81, 82, 83, 85, 86, 87, 88, 91, 92, 93, 94, 96, 97

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 28.

This is the complement of A231000.

Links

Table of n, a(n) for n=1..73.

Time And Date, Repeating Calendar

Time And Date, Julian Calendar

Prog

(PARI) for(i=0, 420, j=0; for(y=0, 420, if(((5*(y\4)+(y%4))%7)==((5*((y+i)\4)+((y+i)%4))%7), j=1)); if(j==0, print1(i", ")))

Crossrefs

Cf. A230995-A231014.

Cf. A230998 (Gregorian calendar).

Sequence in context: A305441 A121405 A330217 * A171551 A096199 A104576

Adjacent sequences: A231000 A231001 A231002 * A231004 A231005 A231006

Keyword

nonn,easy

Author

Aswini Vaidyanathan, Nov 02 2013

Status

approved