

A230998


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


1



1, 2, 3, 4, 8, 9, 10, 13, 14, 15, 16, 19, 20, 21, 24, 25, 26, 27, 30, 31, 32, 36, 37, 38, 41, 42, 43, 44, 47, 48, 49, 52, 53, 54, 55, 58, 59, 60, 64, 65, 66, 69, 70, 71, 72, 75, 76, 77, 80, 81, 82, 83, 86, 87, 88, 92, 93, 94, 97, 98, 99, 100, 103, 104, 105, 109, 110, 111
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OFFSET

1,2


COMMENTS

In the Gregorian calendar, a noncentury year is a leap year if and only if it is a multiple of 4 and a century year is a leap year if and only if it is a multiple of 400.
Assuming this fact, this sequence is periodic with a period of 400.
This is the complement of A230995.


LINKS

Table of n, a(n) for n=1..68.
Time And Date, Repeating Calendar
Time And Date, Gregorian Calendar


PROG

(PARI) for(i=0, 400, j=0; for(y=0, 400, if(((5*(y\4)+(y%4)(y\100)+(y\400))%7)==((5*((y+i)\4)+((y+i)%4)((y+i)\100)+((y+i)\400))%7), j=1)); if(j==0, print1(i", ")))


CROSSREFS

Cf. A230995A231014.
Cf. A231003 (Julian calendar).
Sequence in context: A291621 A288860 A132115 * A184810 A246293 A047228
Adjacent sequences: A230995 A230996 A230997 * A230999 A231000 A231001


KEYWORD

nonn,easy


AUTHOR

Aswini Vaidyanathan, Nov 02 2013


STATUS

approved



