login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A050246 Digital clock primes. 16
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. 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 14 15:12 EDT 2019. Contains 328019 sequences. (Running on oeis4.)