A240839 Both n and prime(n) are primes congruent to 3 (mod 10).

23, 103, 293, 503, 823, 883, 953, 983, 1033, 1163, 1213, 1223, 1433, 1453, 1493, 1523, 1723, 1733, 1933, 1993, 2113, 2203, 2803, 2833, 2903, 3023, 3203, 3343, 3433, 3733, 3823, 3833, 4003, 4243, 4373, 4483, 4513, 4733, 4813, 4903, 4943, 4993, 5333, 5503, 5743, 6143, 6343, 6833, 7013

Offset

1,1

Comments

Intersection of A030431 and A049508.

Links

Zak Seidov, Table of n, a(n) for n = 1..469

Example

prime(23, 103, 293, 503, 823, 883, 953, 983, 1033, 1163)  =  (83, 563, 1913, 3593, 6323, 6863, 7523, 7753, 8233, 9403).

Mathematica

Intersection[A030431 = Select[Range[3, 1000003, 10], PrimeQ], PrimePi[A030431]] (* gives 469 terms for prime(n) up to 10^6 *)
Select[Prime[Range[50000]], Mod[#, 10]==Mod[Prime[#], 10]==3&] (* gives 3126 terms from the first 50000 primes *)(* Harvey P. Dale, Nov 29 2014 *)

Prog

(PARI) s=[]; forprime(n=2, 8000, if(n%10==3 && prime(n)%10==3, s=concat(s, n))); s \\ Colin Barker, Apr 16 2014

Crossrefs

Cf. A030431, A049508.

Sequence in context: A241746 A142192 A129918 * A138715 A096324 A044274

Adjacent sequences: A240836 A240837 A240838 * A240840 A240841 A240842

Keyword

nonn

Author

Zak Seidov, Apr 13 2014

Status

approved