%I A090651
%S A090651 3,4,5,13,1,2,3,11,6,7,1,9,4,5,6,14,2,3,4,12,7,1,2,10,5,6,7,8,3,4,5,13,
%T A090651 1,2,3,11,6,7,1,9,4,5,6,14,2,3,4,12,7,1,2,10,5,6,7,8,3,4,5,13,1,2,3,11,
%U A090651 6,7,1,9,4,5,6,14,2,3,4,12,7,1,2,10,5,6,7,8,3,4,5,13,1,2,3,11,6,7,1,9,
               4
%N A090651 Perpetual calendar sequence: There are 14 basic year calendars, 7 for 
               normal years and 7 for leap years. This sequence identifies the calendars 
               for years 1901 through 2099, when it reinitializes because 2100 is 
               not a leap year.
%C A090651 2000 was a leap year, so no reinitializing was needed.
%C A090651 Calendars are continuous so they roll from Dec 31 to Jan 01. The intercalation 
               of the leap years causes the unusual sequence.
%C A090651 Note that a(n) = 1 for years starting on a Sunday, 2 for years starting 
               on a Monday, so on to 7; 8 for leap years starting on a Sunday, 9 
               for leap years starting on Monday, so on to 14. - Alonso Delarte 
               (alonso.delarte(AT)gmail.com), Nov 02 2004
%D A090651 World Almanac 2003, Perpetual calendar on pages 647-648
%e A090651 a(2003) = 4 because 2003 is a year starting on a Wednesday.
%e A090651 a(2004) = 5 because 2004 is a leap year starting on a Thursday.
%Y A090651 Sequence in context: A010752 A049929 A060738 this_sequence A062201 A049895 
               A051530
%Y A090651 Adjacent sequences: A090648 A090649 A090650 this_sequence A090652 A090653 
               A090654
%K A090651 nonn
%O A090651 1901,1
%A A090651 Brendan Sullivan (bsulliva(AT)austarnet.com.au), Dec 13 2003
%E A090651 More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Dec 23 
               2003