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A327346 The 74 prime dates of each year of the form concatenate(day,month) without leading zeros for month (and day). 6
11, 31, 41, 61, 71, 101, 131, 151, 181, 191, 211, 241, 251, 271, 281, 311, 13, 23, 43, 53, 73, 83, 103, 113, 163, 173, 193, 223, 233, 263, 283, 293, 313, 17, 37, 47, 67, 97, 107, 127, 137, 157, 167, 197, 227, 257, 277, 307, 317, 19, 29, 59, 79, 89, 109, 139, 149, 179, 199, 229, 239, 269, 211, 311, 811, 911, 1511, 1811, 2011, 2111, 2311, 2411, 2711, 3011 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All these prime dates come from January, March, July, September and November, in the form d.m with no 0 in front of the months m = 1, 3, 7, and 9, with 16, 17, 16, 13 and 12 dates, respectively, which sum to 74.

There are just two duplicates, 211 and 311.

LINKS

Table of n, a(n) for n=1..74.

MATHEMATICA

Select[Flatten@ Array[Function[{m, d}, Array[FromDigits[IntegerDigits[#]~Join~m] &, d]] @@ {IntegerDigits@ #, Which[MemberQ[{4, 6, 9, 11}, #], 30, # == 2, 28, True, 31]} &, 12], PrimeQ] (* Michael De Vlieger, Oct 03 2019 *)

CROSSREFS

Cf. A030430 (first 16 members), A030431 (17 members, starting with n=2), A030432 (16 members starting with n=2), A030433 (first 13 members), A167442 (12 members starting with n=2).

Cf. A327347 (54 prime dates d.m with leading 0 for months m = 1, 3, 7, 9), A327348 (66 prime dates m.d for non-leap years), A327349 (67 prime dates, like A327348 but for leap years), A327914 (58 prime dates m.d in non-leap years, with leading 0 for d = 1..9), A327915 (59 prime dates, like A327914, but for leap years).

Sequence in context: A038351 A068871 A004615 * A030430 A059313 A040975

Adjacent sequences:  A327343 A327344 A327345 * A327347 A327348 A327349

KEYWORD

nonn,easy,fini,full

AUTHOR

Wolfdieter Lang, Sep 30 2019

STATUS

approved

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Last modified January 20 21:46 EST 2022. Contains 350472 sequences. (Running on oeis4.)