

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
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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. 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


KEYWORD

nonn,easy,base,fini,full


AUTHOR

Eric W. Weisstein


STATUS

approved



