A227409
Prime numbers representing a date in "condensed American notation" MMDDYY.
Original entry on oeis.org
10103, 10111, 10133, 10139, 10141, 10151, 10159, 10163, 10169, 10177, 10181, 10193, 10211, 10223, 10243, 10247, 10253, 10259, 10267, 10271, 10273, 10289, 10301, 10303, 10313, 10321, 10331, 10333, 10337, 10343, 10357, 10369, 10391, 10399, 10427, 10429, 10433
Offset: 1
a(1)=10103 is prime and represents a date in MMDDYY format as 010103.
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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 d + y + 10000 m;If[PrimeQ[a], AppendTo[t, a]], {d, 1, b}], {m, 1, 12}, {y, 1, 99}]; Union[t]
A227411
Palindromic prime numbers representing a date in "condensed European notation" DDMMYY.
Original entry on oeis.org
10301, 10501, 10601, 30103, 30203, 30403, 30703, 30803, 31013, 70207, 70507, 70607, 90709, 91019
Offset: 1
a(1)=10103 is prime and represents a date in DDMMYY format as 010103.
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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]
A352947
Prime numbers representing a date based on the proleptic Gregorian calendar in YY..YMMDD format.
Original entry on oeis.org
10103, 10111, 10211, 10223, 10301, 10303, 10313, 10321, 10331, 10427, 10429, 10501, 10513, 10529, 10531, 10601, 10607, 10613, 10627, 10709, 10711, 10723, 10729, 10831, 10903, 10909, 11003, 11027, 11113, 11117, 11119, 11213, 20101, 20107, 20113, 20117, 20123
Offset: 1
20050403 is a term because the date 'Apr 3, 2005' represented in YY..YMMDD format is 20050403, which is a prime number.
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from sympy import isprime
for y in range(1, 3):
for m in range(1, 13):
d_max = 31 if m in {1, 3, 5, 7, 8, 10, 12} else 30 if m in {4, 6, 9, 11} else 28 if (y%4 or (y%400 and not y%100)) else 29
for d in range(1, d_max + 1):
date = 10000*y + 100*m + d
if isprime(date): print(date, end = ', ')
Showing 1-3 of 3 results.
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