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A202113 Numbers n such that 90n + 61 is prime. 6

%I #13 Feb 17 2017 15:33:29

%S 0,1,2,3,4,6,7,11,13,14,20,21,23,24,25,29,31,34,36,37,39,43,44,45,46,

%T 50,51,53,55,56,58,62,64,67,69,70,71,77,81,84,90,93,94,99,101,102,104,

%U 105,106,108,109,112,114,116,119,120,123,125,127,132,135,136

%N Numbers n such that 90n + 61 is prime.

%C This sequence was generated by adding 14 Fibonacci-like sequences [See: PROG]. Looking at the format 90n+61 modulo 9 and modulo 10 we see that all entries of A142330 have digital root 7 and last digit 1. (Reverting the process is an application of the Chinese remainder theorem.) The 14 Fibonacci-like sequences are generated (via the p and q values given in the Perl program) from the base p,q pairs 61*91, 19*79, 37*43, 73*7, 11*71, 29*89, 47*53, 83*17, 13*67, 31*31, 49*49, 23*77, 41*41, 59*59.

%t Select[Range[0, 200], PrimeQ[90 # + 61] &]

%o (PARI) is(n)=isprime(90*n+61) \\ _Charles R Greathouse IV_, Feb 17 2017

%Y Cf. A181732, A198382, A195993, A196000, A196007, A201739, A201734, A201804, A201816, A201817, A201818, A201820, A201822, A202101, A202104, A202105, A202110, A202112.

%K nonn,easy

%O 1,3

%A _J. W. Helkenberg_, Dec 11 2011

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Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)