OFFSET
1,1
COMMENTS
LINKS
EXAMPLE
5 belongs to this sequence because January 1, 2012 falls on same day as January 1, 2017 but the calendar is not completely the same for both the years. In fact, a difference of 5 years can never produce the same calendar for the entire year.
7 belongs to this sequence because January 1, 2097 falls on same day as January 1, 2104 but the calendar is not completely the same for both the years. In fact, a difference of 7 years can never produce the same calendar for the entire year.
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; break)); 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)&&((5*(y\4)+(y%4)-(y\100)+(y\400)-!(y%4)+!(y%100)-!(y%400))%7)==((5*((y+i)\4)+((y+i)%4)-((y+i)\100)+((y+i)\400)-!((y+i)%4)+!((y+i)%100)-!((y+i)%400))%7), j=2; break)); if(j==1, print1(i", ")))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Aswini Vaidyanathan, Nov 02 2013
STATUS
approved