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A260915 Prime number days: prime numbers that can be interpreted as an ISO date. 1
10000103, 10000121, 10000223, 10000303, 10000511, 10000609, 10000721, 10000723, 10000813, 10000819, 10000831, 10001009, 10001107, 10001119, 10001203, 10001207, 10001209, 10001213, 10001221, 10001227, 10001231, 10010101, 10010113, 10010213, 10010227, 10010311, 10010317, 10010323, 10010401 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

An ISO date is in the format YYYY-MM-DD.

The last term of this sequence is 99991207.

LINKS

Christian Perfect, Table of n, a(n) for n = 1..24974

MEI Maths item of the month.

Date and time format - ISO 8601.

EXAMPLE

20150821 belongs to this sequence because it is prime and represents the 21st of August 2015.

MATHEMATICA

d = Sort@ Join[Flatten[Plus[{100, 300, 500, 700, 800, 1000, 1200}, #] & /@ Select[Range[1, 31, 2], ! Mod[#, 5] == 0 &]], Flatten[Plus[{200, 400, 600, 900, 1100}, #] & /@ Select[Range[1, 29, 2], ! Mod[#, 5] == 0 &]]]; Select[Flatten[Plus[If[Or[Mod[#, 10000000] == 0, Mod[#, 40000] == 0 && ! Mod[#, 1000000] == 0], d, Delete[d, 25]], #] & /@ (10000 Range[1000, 1001])], PrimeQ] (* Michael De Vlieger, Aug 04 2015 *)

PROG

(Python)

import datetime

.

def prime_number_days():

...j = 0

...date = datetime.date(1000, 1, 1)

...while date.year<2100:

......x = int(date.strftime("%Y%m%d"))

......while primes[j]<x:

.........j += 1

......if primes[j]==x:

.........yield x

......date += datetime.timedelta(days=1)

CROSSREFS

Cf. A000040 (prime numbers).

Sequence in context: A017515 A017647 A182749 * A072144 A087510 A173002

Adjacent sequences:  A260912 A260913 A260914 * A260916 A260917 A260918

KEYWORD

nonn,easy,fini,base

AUTHOR

Christian Perfect, Aug 04 2015

STATUS

approved

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Last modified May 24 18:12 EDT 2022. Contains 354043 sequences. (Running on oeis4.)