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A158614 Numbers n such that 30*n + 11 is prime. 9

%I #17 Feb 17 2017 14:32:38

%S 0,1,2,3,4,6,8,9,10,13,14,15,16,17,21,23,25,27,29,30,31,32,34,35,36,

%T 38,39,43,45,48,49,50,52,53,57,60,62,63,64,69,70,71,78,79,80,81,84,86,

%U 87,90,91,93,95,100,101,106,107,108,112,115,116,119,122,123,125,127,128

%N Numbers n such that 30*n + 11 is prime.

%C Encoded primes with LSD 1 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 of the quotient is in the sequence, the number is prime.

%H Ivan Neretin, <a href="/A158614/b158614.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = (A132232(n) - 11)/30 = floor(A132232(n)/30). - _Ray Chandler_, Apr 07 2009

%e Example: 3191, with LSD 1 and (SOD-1)/3 = 4.33 (non-integer); Then 3191/30=106.367, or 106 which is in the sequence, thus 3191 is prime.

%t Select[Range[0,130],PrimeQ[30#+11]&] (* _Harvey P. Dale_, Jul 26 2011 *)

%o (PARI) is(n)=isprime(30*n+11) \\ _Charles R Greathouse IV_, Feb 17 2017

%Y Cf. A111175, A158573, A158648, A158746, A158791, A158806, A158850.

%K nonn

%O 1,3

%A _Ki Punches_, Mar 22 2009, Mar 29 2009

%E Edited by _Ray Chandler_, Apr 07 2009

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)