A158746 Numbers n such that 30*n + 13 is prime.

0, 1, 2, 3, 5, 6, 7, 9, 10, 12, 14, 15, 17, 20, 21, 22, 24, 27, 28, 29, 34, 35, 36, 37, 38, 40, 43, 47, 48, 49, 51, 55, 56, 57, 58, 59, 62, 64, 66, 68, 69, 70, 71, 73, 76, 79, 82, 83, 86, 89, 90, 93, 94, 98, 105, 108, 110, 111, 112, 114, 115, 119, 120, 121, 122, 124, 126, 127

Offset

1,3

Comments

Encoded primes with LSD 3, (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

Table of n, a(n) for n=1..68.

Formula

a(n) = (A132233(n) - 13)/30 = Floor[A132233(n)/30]. - Chandler

Example

Example: 3163, with LSD 3 and (SOD-1)/3 = 4 (integer); Then 3163/30 = 105.433, or 105 which is in the sequence, thus 3163 is prime.

Mathematica

Select[Range[0, 200], PrimeQ[30#+13]&] (* Harvey P. Dale, Oct 16 2018 *)

Prog

(PARI) is(n)=isprime(30*n+13) \\ Charles R Greathouse IV, Feb 17 2017

Crossrefs

Cf. A111175, A158573, A158614, A158648, A158791, A158806, A158850.

Sequence in context: A248229 A207672 A038161 * A062470 A179460 A344281

Adjacent sequences: A158743 A158744 A158745 * A158747 A158748 A158749

Keyword

nonn

Author

Ki Punches, Mar 25 2009

Extensions

Edited by Ray Chandler, Apr 07 2009

Status

approved