A295013 Prime time primes on 6-digit clocks, second definition: primes of the form HMMSS where H, MM, SS are primes, H < 24, MM and SS < 60.

20219, 20231, 20261, 20297, 20323, 20341, 20347, 20353, 20359, 20389, 20507, 20543, 20707, 20717, 20719, 20731, 20743, 20747, 20753, 20759, 20771, 20773, 20789, 21107, 21143, 21179, 21313, 21317, 21319, 21323, 21341, 21347, 21379, 21383, 21397, 21713

Offset

1,1

Comments

A subsequence and variant of A229106, where the individual digit groups are not required to be primes. Also a subsequence (namely, the prime terms) of A295014, where H, MM and SS must be primes, but not the concatenation HMMSS.

See A295000 for the subsequence of terms for which the number of seconds after midnight (3600*H + 60*MM + SS, listed in A295003) is also prime.

Links

M. F. Hasler, Table of n, a(n) for n = 1..1211 (complete sequence).

Mathematica

With[{s = Prime@ Range@ PrimePi@ 60}, Select[FromDigits@ Flatten[PadLeft[IntegerDigits[#], 2] & /@ #] & /@ Tuples@ {TakeWhile[s, # < 24 &], s, s}, PrimeQ]] (* Michael De Vlieger, Jan 21 2018 *)

Prog

(PARI) is_A295013(n)=apply(isprime, digits(n, 100))==[1, 1, 1]&&n<24e4&&isprime(n)
A295013 = select( is_A295013, primes([20000, 240000]))

Crossrefs

Cf. A050246, A159911, A229106; A118848, A118849, A118850.

Cf. A295014, A295003, A295011, A295000, A295002.

Sequence in context: A133527 A295011 A146961 * A295000 A250451 A031825

Adjacent sequences: A295010 A295011 A295012 * A295014 A295015 A295016

Keyword

nonn,base,fini,full

Author

M. F. Hasler, Jan 09 2018

Status

approved