cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-6 of 6 results.

A295000 Prime time primes (of the form HMMSS with primes H < 24 and MM, SS < 60) such that the corresponding number of seconds after midnight is also prime.

Original entry on oeis.org

20231, 20297, 20353, 20507, 20719, 20753, 20771, 21107, 21313, 21379, 21713, 21767, 21773, 21929, 21937, 22343, 22367, 22397, 22961, 22973, 23131, 23143, 23167, 23173, 23197, 23719, 23741, 23743, 23747, 23753, 24137, 24179, 24337, 24359, 24371, 24379
Offset: 1

Views

Author

M. F. Hasler, Jan 15 2018

Keywords

Comments

Could be called "super prime time primes": all of H, MM, SS, HMMSS (6-digit clock display) and H*3600 + MM*60 + SS (seconds after midnight) are prime.
This sequence lists the prime time primes A295013 for which the number of seconds A295003 is prime. These are also the times HMMSS (obtained through A055643) which correspond to the subset A295002 of primes in A295003.
Sequence A295002 lists the number of seconds after midnight corresponding to the "prime times" = 6-digit clock displays listed here.
Sequences A295003 and A295004 list the number of seconds after midnight corresponding to the prime time primes A295013 and prime time numbers A295014, i.e., primes and all numbers of the form HMMSS where H < 24 and MM, SS < 60 are prime.

Examples

			The smallest prime of the form HMMSS, with H, MM, SS and H*3600 + MM*60 + SS also prime, is a(1) = 20231, corresponding to a prime number A295002(1) = H*3600 + MM*60 + SS = 7351 (the first prime in A295003) of seconds after midnight.
		

Crossrefs

Programs

Formula

a(n) = A055643(A295002(n)) ; A295000 = { A295013(k) | A295003(k) is prime }.

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.

Original entry on oeis.org

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

Views

Author

M. F. Hasler, Jan 09 2018

Keywords

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.

Crossrefs

Programs

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

A295014 Prime time numbers on 6-digit clocks: numbers of the form HMMSS where H, MM, SS are primes, H < 24, MM and SS < 60.

Original entry on oeis.org

20202, 20203, 20205, 20207, 20211, 20213, 20217, 20219, 20223, 20229, 20231, 20237, 20241, 20243, 20247, 20253, 20259, 20302, 20303, 20305, 20307, 20311, 20313, 20317, 20319, 20323, 20329, 20331, 20337, 20341, 20343, 20347, 20353, 20359, 20502, 20503
Offset: 1

Views

Author

M. F. Hasler, Jan 09 2018

Keywords

Comments

The primes in this sequence form the subsequence A295013, a variant and subsequence of A229106, where only the concatenation HMMSS but not the individual digit groups are required to be primes. See also A050246 and A159911 for 4-digit clock variants.
See A295011 for the subsequence of terms for which the number of seconds after midnight (3600*H + 60*MM + SS, given in A295004) is prime, and A295000 for the subsequence of primes therein.

Crossrefs

Programs

  • Mathematica
    With[{s = Prime@ Range@ PrimePi@ 60}, FromDigits@ Flatten[PadLeft[IntegerDigits[#], 2] & /@ #] & /@ Tuples@ {TakeWhile[s, # < 24 &], s, s}] (* Michael De Vlieger, Jan 21 2018 *)
  • PARI
    is_A295014(n)=apply(isprime,digits(n,100))==[1,1,1]&&n<24e4
    A295014 = select( is_A295014, [20000,240000])
    /* alternatively */ A295014=List(); forprime(h=0,24,forprime(m=0,60,forprime(s=0,60,listput(A295014,(h*100+m)*100+s))))

A295002 Primes in A295003, the number of seconds after midnight corresponding to prime time primes A295013 (primes of the form HMMSS with primes H < 24 and MM, SS < 60).

Original entry on oeis.org

7351, 7417, 7433, 7507, 7639, 7673, 7691, 7867, 7993, 8059, 8233, 8287, 8293, 8369, 8377, 8623, 8647, 8677, 9001, 9013, 9091, 9103, 9127, 9133, 9157, 9439, 9461, 9463, 9467, 9473, 9697, 9739, 9817, 9839, 9851, 9859, 10453, 10753, 10771, 10837, 10867, 10949
Offset: 1

Views

Author

M. F. Hasler, Jan 15 2018

Keywords

Comments

See A295000(n) = A055643(a(n)) for the corresponding "prime time primes", i.e., 6-digit clock displays. Reciprocally, the number of seconds given here is obtained through A292579 from the "super prime time primes" A295000.

Crossrefs

Programs

Formula

a(n) = A292579(A295000(n))

A295003 The number of seconds after midnight corresponding to prime time primes, i.e., primes of the form HMMSS with primes H < 24 and MM, SS < 60, cf. A295013.

Original entry on oeis.org

7339, 7351, 7381, 7417, 7403, 7421, 7427, 7433, 7439, 7469, 7507, 7543, 7627, 7637, 7639, 7651, 7663, 7667, 7673, 7679, 7691, 7693, 7709, 7867, 7903, 7939, 7993, 7997, 7999, 8003, 8021, 8027, 8059, 8063, 8077, 8233, 8257, 8287, 8293, 8351, 8369, 8377, 8383
Offset: 1

Views

Author

M. F. Hasler, Jan 15 2018

Keywords

Comments

See A295002 for the primes within this sequence, and A295000 for the corresponding 6-digit clock times.

Crossrefs

Programs

  • Mathematica
    With[{s = Prime@ Range@ PrimePi@ 60}, Select[NumberCompose[{#1, #2, #3}, {3600, 60, 1}] & @@ # & /@ Tuples@ {TakeWhile[s, # < 24 &], s, s}, PrimeQ]] (* Michael De Vlieger, Jan 21 2018 *)
  • PARI
    apply( A292579, A295013) \\ convert prime time primes to seconds

A295004 The number of seconds after midnight (3600*H + 60*MM + SS) corresponding to prime time numbers A295014, i.e., numbers of the form HMMSS with primes H < 24 and MM, SS < 60.

Original entry on oeis.org

7322, 7323, 7325, 7327, 7331, 7333, 7337, 7339, 7343, 7349, 7351, 7357, 7361, 7363, 7367, 7373, 7379, 7382, 7383, 7385, 7387, 7391, 7393, 7397, 7399, 7403, 7409, 7411, 7417, 7421, 7423, 7427, 7433, 7439, 7502, 7503, 7505, 7507, 7511, 7513, 7517, 7519, 7523
Offset: 1

Views

Author

M. F. Hasler, Jan 15 2018

Keywords

Comments

See A295003 for the subsequence of terms which correspond to "prime time primes" (cf. A295013), and A295002 for the primes among these.
This is to A295014 what is A295003 to A295013, or what is A118848 to A050246, or what is A118850 to A118849.

Crossrefs

Programs

  • Mathematica
    With[{s = Prime@ Range@ PrimePi@ 60}, NumberCompose[{#1, #2, #3}, {3600, 60, 1}] & @@ # & /@ Tuples@ {TakeWhile[s, # < 24 &], s, s}] (* Michael De Vlieger, Jan 21 2018 *)
  • PARI
    apply( A292579, A295014) \\ convert prime time numbers to seconds

Formula

a(n) = A292579(A295014(n))
Showing 1-6 of 6 results.