Search: id:A090651 Results 1-1 of 1 results found. %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 Search completed in 0.001 seconds