A076746 List giving pairs of primes of the form 10k+3 and 10k+7.
3, 7, 13, 17, 43, 47, 103, 107, 163, 167, 193, 197, 223, 227, 313, 317, 463, 467, 613, 617, 643, 647, 673, 677, 823, 827, 853, 857, 883, 887, 1093, 1097, 1213, 1217, 1303, 1307, 1423, 1427, 1483, 1487, 1663, 1667, 1693, 1697, 1783, 1787, 1873, 1877, 1993
Offset: 1
Keywords
Examples
43 and 47 are in the sequence because both are prime; 73 and 77 aren't because not both are primes.
Links
- Roger L. Bagula, May 04 2008, Table of n, a(n) for n = 1..142
Programs
-
Magma
&cat[[10*k+3, 10*k+7]: k in [0..250]| IsPrime(10*k+3) and IsPrime(10*k+7)]; // Vincenzo Librandi, Jun 17 2016
-
Mathematica
a[0] = 3; a[n_] := a[n] = a[n - 1] + 10; Flatten[Table[If[PrimeQ[a[n]] && PrimeQ[a[n] + 4], {a[n],a[n] + 4}, {}], {n, 0, 1000}]] (* Roger L. Bagula, May 04 2008 *) Flatten[Select[Table[10n+{3,7},{n,0,200}],And@@PrimeQ[#]&]] (* Harvey P. Dale, Dec 31 2013 *) -
PARI
forstep(x=3,2000,10, if(isprime(x) && isprime(x+4), print1(x, ", ", x+4, ", ")))
Extensions
Edited by Don Reble, Jun 07 2003
More terms from Roger L. Bagula, May 04 2008
Comments