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%I #15 Sep 01 2023 11:33:48
%S 101,103,107,109,113,127,131,211,223,227,229,307,311,313,317,331,401,
%T 409,419,421,503,509,521,523,601,607,613,617,619,701,709,719,727,809,
%U 811,821,823,827,829,901,911,919,929,1009,1013,1019,1021,1031,1103,1109,1117,1123,1129,1201,1213,1217,1223,1229,1231
%N The 59 prime dates of each leap year of the form concatenate(month,day) with leading zero for days 1..9.
%C In leap years all these dates come from the months January, February, ..., December, in the form m.d, with a 0 in front of the days d = 1..9, with 7, 4, 5, 4, 4, 5, 4, 6, 4, 5, 5, 6 prime dates, respectively, adding up to 59. For the corresponding leap year case with 58 prime dates see A327914.
%C Compared with A327349 (leap years, no 0's before days d = 1..9) one has the same differences as given in a comment in A327914 (229 appears in the present sequence and in A327349).
%t Select[Flatten@ Array[Function[{m, d}, Array[FromDigits[m~Join~PadLeft[IntegerDigits[#], 2]] &, d]] @@ {IntegerDigits@ #, Which[MemberQ[{4, 6, 9, 11}, #], 30, # == 2, 29, True, 31]} &, 12], PrimeQ] (* _Michael De Vlieger_, Oct 03 2019 *)
%t fd[{m_,d_}]:=FromDigits[Flatten[{m,PadLeft[{d},2,0]}]]; Select[fd[Take[#,{2,3}]]&/@ DateRange[ {2024,1,1},{2024,12,31}],PrimeQ] (* _Harvey P. Dale_, Sep 01 2023 *)
%Y Cf. A327346 (74 prime dates d.m without leading 0 for month), 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, the case for non-leap years).
%K nonn,easy,fini,full
%O 1,1
%A _Wolfdieter Lang_, Sep 30 2019
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