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%I #34 Dec 06 2015 22:45:23
%S 10301,10501,10601,30103,30203,30403,30703,30803,31013,70207,70507,
%T 70607,90709,91019
%N Palindromic prime numbers representing a date in "condensed European notation" DDMMYY.
%C For February, the number of days will be 28 only, as year cannot be a leap year for DDMMYY to be a prime number.
%C The sequence is finite, with 14 terms. The largest term is a(14)=91019.
%C There are no 6-digit solutions - the month must be 11 and the day cannot start with a 0 or a 2. Nor can the day start with a 1 because this makes the palindrome of the form 1x11x1 - divisible by 1001. This leaves only 301103, which is 11*31*883, so not prime. - _Jon Perry_, Sep 23 2013
%e a(1)=10103 is prime and represents a date in DDMMYY format as 010103.
%t palindromicQ[n_] := TrueQ[IntegerDigits[n] == Reverse[IntegerDigits[n]]]; t = {}; Do[If[m < 8, If[OddQ[m], b = 31, If[m == 2, b = 28, b = 30]], If[OddQ[m], b = 30, b = 31]]; Do[a = 100 m + y + 10000 d; If[PrimeQ[a] && palindromicQ[a], AppendTo[t, a]], {d, 1, b}], {m, 1, 12}, {y, 1, 99}]; Union[t]
%Y Cf. A213182, A227407, A227410.
%K nonn,base,fini,full,less
%O 1,1
%A _Shyam Sunder Gupta_, Sep 22 2013
%E Incorrect a(15)-a(32) from _Vincenzo Librandi_, Sep 23 2013 removed. - _Jon Perry_, Sep 24 2013
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