

A190653


Years with exactly three "Friday the 13ths", starting from 1901.


4



1903, 1914, 1925, 1928, 1931, 1942, 1953, 1956, 1959, 1970, 1981, 1984, 1987, 1998, 2009, 2012, 2015, 2026, 2037, 2040, 2043, 2054, 2065, 2068, 2071, 2082, 2093, 2096, 2099, 2105, 2108, 2111, 2122, 2133, 2136, 2139, 2150, 2161, 2164, 2167, 2178, 2189, 2192
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OFFSET

1,1


COMMENTS

A101312(a(n)) = 3, 1 <= A101312(n) <= 3.


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Triskaidekaphobia
Wikipedia, Triskaidekaphobia
Index entries for sequences related to calendars


EXAMPLE

A101312(2012) = #{January, April, July} = 3, therefore 2012 is a term.


PROG

(Haskell)
a190653 n = a190653_list !! (n1)
a190653_list = filter ((== 3) . a101312) [1901..]


CROSSREFS

Cf. A190651, A190652.
Sequence in context: A177137 A190651 A237787 * A124628 A112947 A206124
Adjacent sequences: A190650 A190651 A190652 * A190654 A190655 A190656


KEYWORD

nonn


AUTHOR

Reinhard Zumkeller, May 16 2011


STATUS

approved



