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A057347 Leap years in the Islamic calendar starting year 1 AH (Anno Hegirae) = 622 CE (Common Era or AD). There are 11 leap years in a 30 year cycle. 5
2, 5, 7, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40, 43, 46, 48, 51, 54, 56, 59, 62, 65, 67, 70, 73, 76, 78, 81, 84, 86, 89, 92, 95, 97, 100, 103, 106, 108, 111, 114, 116, 119, 122, 125, 127, 130, 133, 136, 138, 141, 144, 146, 149, 152, 155, 157, 160, 163, 166 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

An Islamic year approximates 12 lunar months with 354 11/30 days (or 30 years with 10631 days).

Also, numbers m such that ((14 + 11*m) mod 30) < 11.

REFERENCES

N. Dershowitz and E. M. Reingold, Calendrical Calculations, Cambridge University Press, 1997.

LINKS

Table of n, a(n) for n=1..61.

Index entries for sequences related to calendars

FORMULA

a(n) = floor((30*n - 4)/11).

MATHEMATICA

Select[Range[100], LeapYearQ[{#}, CalendarType -> "Islamic"]&] (* Jean-François Alcover, Apr 26 2020 *)

CROSSREFS

Cf. A057349 (Hebrew calendar leap years).

Cf. A057348 (Islamic months lengths), A008685 (Gregorian months lengths),

Cf. A350539 (Islamic New Year JDN and 8 Islamic calendar variants).

Sequence in context: A344988 A255774 A081838 * A067008 A189757 A094065

Adjacent sequences: A057344 A057345 A057346 * A057348 A057349 A057350

KEYWORD

nonn,easy

AUTHOR

Mitch Harris

STATUS

approved

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Last modified November 27 03:51 EST 2022. Contains 358362 sequences. (Running on oeis4.)