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A050246
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Digital clock primes.
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17
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2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 211, 223, 227, 229, 233, 239, 241, 251, 257, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 401, 409, 419, 421, 431, 433, 439, 443
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OFFSET
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1,1
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COMMENTS
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The number of minutes past midnight represented by each of the times here can be found in A118848. - Carl R. White, May 01 2006
Equals the first 211 terms of A229106, corresponding to interpretation as minutes and seconds what are hours and minutes here. - M. F. Hasler, Jan 09 2018
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LINKS
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Nathaniel Johnston, Table of n, a(n) for n = 1..211 (full sequence)
Randall Munroe, Factoring the time, xkcd Web Comic #247, Apr 11 2007.
Eric Weisstein's World of Mathematics, Clock Prime.
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FORMULA
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a(n) = A118848(n) + floor(A118848(n)/60)*40. - Carl R. White, May 01 2006
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EXAMPLE
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a(143) = 1453 is shown in the last panel of Randall Munroe's Web Comic #247.
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MAPLE
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for h from 0 to 23 do for m from 0 to 59 do t:=100*h+m: if(isprime(t))then printf("%d, ", t): fi: od: od: # Nathaniel Johnston, May 17 2011
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PROG
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(PARI) A050246 = select( t -> t%100 < 60, primes([1, 2399])) \\ M. F. Hasler, Jan 09 2018
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CROSSREFS
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Cf. A118848, A118849, A118850, A129336, A316603.
Cf. A159911, where hours H and minutes MM must also be prime, separately.
Sequence in context: A078668 A038614 A171047 * A229106 A118849 A049561
Adjacent sequences: A050243 A050244 A050245 * A050247 A050248 A050249
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KEYWORD
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nonn,easy,base,fini,full
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AUTHOR
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Eric W. Weisstein
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STATUS
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approved
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