A158806 Numbers n such that 30*n + 19 is prime.

0, 2, 3, 4, 6, 7, 11, 12, 13, 14, 16, 20, 23, 24, 25, 27, 28, 30, 33, 34, 35, 37, 41, 42, 46, 47, 48, 49, 51, 52, 53, 55, 56, 58, 59, 62, 66, 67, 69, 72, 74, 75, 79, 84, 88, 89, 90, 91, 100, 101, 102, 103, 105, 107, 108, 110, 115, 116, 117, 118, 123, 124, 125, 129, 130

Offset: 1

Author

Ki Punches, Mar 27 2009

Keywords

• nonn

Comments

Encoded primes with LSD 9, (SOD-1)/3 integer, (LSD, least significant digit; SOD, sum of digits). Divide any such number by 30, if the whole number portion of the quotient is in the sequence, the number is prime.

Examples

			Example: 3019, with LSD 9, (SOD-1)/3 integer; Then 3019/30 = 100.633, or 100, which is in the sequence, thus 3019 is prime.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A111175, A158573, A158614, A158648, A158746, A158791, A158850.

Programs

Mathematica

Select[Range[0,150],PrimeQ[30#+19]&] (* Harvey P. Dale, Apr 05 2025 *)

PARI

is(n)=isprime(30*n+19) \\ Charles R Greathouse IV, Feb 17 2017

Formula

a(n) = (A132234(n) - 19)/30 = Floor[A132234(n)/30]. - Chandler

Extensions

Edited by Ray Chandler, Apr 07 2009