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

1,2

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.

Links

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

Formula

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

Example

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.

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A050679 A342684 A344625 * A184966 A018723 A088412

Adjacent sequences: A158803 A158804 A158805 * A158807 A158808 A158809

Keyword

nonn

Author

Ki Punches, Mar 27 2009

Extensions

Edited by Ray Chandler, Apr 07 2009

Status

approved