OFFSET
1,3
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.
EXAMPLE
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.
PROG
(PARI) is(n)=isprime(30*n+29) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Ki Punches, Mar 28 2009
EXTENSIONS
Edited by Ray Chandler, Apr 07 2009
STATUS
approved