A158850 Numbers n such that 30*n + 29 is prime.

0, 1, 2, 4, 5, 7, 8, 11, 12, 13, 14, 15, 16, 18, 19, 21, 23, 26, 27, 30, 33, 34, 36, 40, 41, 42, 43, 46, 47, 49, 51, 53, 56, 62, 64, 65, 67, 68, 69, 70, 76, 77, 79, 81, 84, 85, 86, 89, 90, 92, 93, 95, 96, 97, 98, 99, 102, 103, 106, 109, 110, 111, 112, 114, 117, 121, 123, 125

Offset: 1

Author

Ki Punches, Mar 28 2009

Keywords

• nonn

Comments

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

Examples

			Example: 3209 with LSD 9 and (SOD-1)/3 non-integer; Then 3209/30 = 106.966, or 106, which is in the sequence, thus 3209 is prime.
		

Crossrefs

Cf. A111175, A158573, A158614, A158648, A158746, A158791, A158806.

Programs

PARI

is(n)=isprime(30*n+29) \\ Charles R Greathouse IV, Feb 17 2017

Formula

a(n) = (A132236(n) - 29)/30 = Floor[A132236(n)/30]. - Chandler

Extensions

Edited by Ray Chandler, Apr 07 2009