A132235 Primes congruent to 23 (mod 30).

23, 53, 83, 113, 173, 233, 263, 293, 353, 383, 443, 503, 563, 593, 653, 683, 743, 773, 863, 953, 983, 1013, 1103, 1163, 1193, 1223, 1283, 1373, 1433, 1493, 1523, 1553, 1583, 1613, 1733, 1823, 1913, 1973, 2003, 2063, 2153, 2213, 2243, 2273, 2333, 2393

Offset: 1

Author

Omar E. Pol, Aug 15 2007

Keywords

• nonn
• easy

Comments

Primes (excluding 3) ending in 3 with (SOD-1)/3 non-integer where SOD is sum of digits. - Ki Punches

The sequence is infinite by Dirichlet's theorem. - Arkadiusz Wesolowski, Apr 02 2014

Terms are non-twin primes A007510. - Omar E. Pol, Jul 25 2019

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• C. K. Caldwell, The Prime Pages.
• Omar E. Pol, Determinacion geometrica de los numeros primos y perfectos.
• Omar E. Pol, Prime numbers in a sieve with 30 columns

Crossrefs

Cf. A000040, A039949.

Cf. A132230, A132231, A132232, A132233, A132234, A132236.

Programs

Magma

[p: p in PrimesUpTo(3000) | p mod 30 eq 23 ]; // Vincenzo Librandi, Aug 14 2012

Mathematica

Select[Prime[Range[1000]],MemberQ[{23},Mod[#,30]]&] (* Vincenzo Librandi, Aug 14 2012 *)
Select[Range[23,2400,30],PrimeQ] (* Harvey P. Dale, Jan 27 2020 *)

PARI

is(n)=isprime(n) && n%30==23 \\ Charles R Greathouse IV, Jul 01 2016

Formula

a(n) = A158791(n)*30 + 23. - Ray Chandler, Apr 07 2009

Intersection of A030431 and A007528. - Ray Chandler, Apr 07 2009

Extensions

Extended by Ray Chandler, Apr 07 2009