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A050246 Digital clock primes. 17
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
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
LINKS
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.
FORMULA
a(n) = A118848(n) + floor(A118848(n)/60)*40. - Carl R. White, May 01 2006
EXAMPLE
a(143) = 1453 is shown in the last panel of Randall Munroe's Web Comic #247.
MAPLE
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
PROG
(PARI) A050246 = select( t -> t%100 < 60, primes([1, 2399])) \\ M. F. Hasler, Jan 09 2018
CROSSREFS
Cf. A159911, where hours H and minutes MM must also be prime, separately.
Sequence in context: A078668 A038614 A171047 * A229106 A118849 A049561
KEYWORD
nonn,easy,base,fini,full
AUTHOR
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)