This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A327349 #13 Dec 17 2024 06:32:40
%S A327349 11,13,17,19,113,127,131,23,29,211,223,227,229,31,37,311,313,317,331,
%T A327349 41,43,47,419,421,53,59,521,523,61,67,613,617,619,71,73,79,719,727,83,
%U A327349 89,811,821,823,827,829,97,911,919,929,101,103,107,109,1013,1019,1021,1031,113,1117,1123,1129,127,1213,1217,1223,1229,1231
%N A327349 The 67 prime dates in each leap year of the form concatenate (month,day) without leading zeros for days.
%C A327349 In a leap year the months 1, 2, ..., 12 contribute 7, 6, 6, 5, 4, 5, 5, 7, 4, 8, 4, 6 such dates. This adds to 67 prime dates. For non-leap years see the 66 prime dates given in A327348.
%t A327349 Select[Flatten@ Array[Function[{m, d}, Array[FromDigits[Join[m, IntegerDigits[#]]] &, d]] @@ {IntegerDigits@ #, Which[MemberQ[{4, 6, 9, 11}, #], 30, # == 2, 29, True, 31]} &, 12], PrimeQ] (* _Michael De Vlieger_, Oct 03 2019 *)
%Y A327349 Cf. A327346 (74 prime dates of the form d.m (no leading 0's for m and d)), A327347 (55 prime dates of the form d.m with leading 0's for m = 1, 3, 7, 9), A327348 (non-leap year case), A327914 (58 prime dates of the form m.d in non-leap years, with leading 0 for d = 1..9), A327915 (59 prime dates like A327914 but for leap years).
%K A327349 nonn,easy,fini,full
%O A327349 1,1
%A A327349 _Wolfdieter Lang_, Sep 30 2019