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A327920 The 16 pure prime dates of each year of the form concatenate(day,month) with month and day also prime numbers. 2
23, 53, 73, 113, 173, 193, 233, 293, 313, 37, 137, 197, 317, 211, 311, 2311 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For the case of the 16, respectively 17, pure prime dates of the form concatenate(month,day) see A327918 (non-leap years) and A327919 (leap years).

Only the three months m = 3, 7, and 11 qualify. The qualifying days are for November (m = 11): d = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, and for months March and July (m = 3 and 7): d = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31.

The months m = 3, 7, 11 contribute 9, 4, 3 dates, respectively, adding to 16.

LINKS

Table of n, a(n) for n=1..16.

CROSSREFS

Cf. A055782 (first nine terms), A055783 (first four terms), A114007 (three terms starting with n = 8). A327346 (with d and m also nonprime allowed), A327918, A327919.

Sequence in context: A140689 A172034 A113912 * A055782 A104802 A128473

Adjacent sequences:  A327917 A327918 A327919 * A327921 A327924 A327925

KEYWORD

nonn,easy,fini,full

AUTHOR

Wolfdieter Lang, Oct 08 2019

STATUS

approved

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Last modified November 13 00:25 EST 2019. Contains 329083 sequences. (Running on oeis4.)