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 A195993 Numbers n such that 90n + 73 is prime. 21
 0, 1, 4, 5, 6, 9, 11, 12, 15, 18, 19, 20, 22, 23, 27, 28, 29, 32, 36, 39, 40, 42, 43, 49, 51, 54, 55, 56, 61, 62, 63, 65, 70, 72, 74, 75, 85, 88, 91, 92, 93, 95, 96, 97, 98, 103, 104, 106, 109, 110, 113, 114, 116, 127, 128, 131 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS This sequence results from the propagation (addition) of 12 Fibonacci-like sequences; this sequence contains (recovers) all digital root 1 and last digit 3 prime numbers. LINKS Ivan Neretin, Table of n, a(n) for n = 1..10000 FORMULA a(n) = (A142326(n)-73)/90. MAPLE A142326 := proc(n)         option remember;         if n = 1 then                 73 ;         else                 a := nextprime(procname(n-1)) ;                 while (a mod 45) <> 28 do                         a := nextprime(a) ;                 end do;                 return a;         end if; end proc: A195993 := proc(n)         (A142326(n)-73)/90 ; end proc: seq(A195993(n), n=1..80) ; # R. J. Mathar, Oct 31 2011 MATHEMATICA Select[Range[0, 200], PrimeQ[90#+73]&] (* Harvey P. Dale, May 05 2014 *) PROG (PARI) is(n)=isprime(90*n+73) \\ Charles R Greathouse IV, Apr 25 2016 CROSSREFS Cf. A181732, A198382. Sequence in context: A162016 A242040 A206822 * A334457 A010456 A072496 Adjacent sequences:  A195990 A195991 A195992 * A195994 A195995 A195996 KEYWORD nonn,easy AUTHOR J. W. Helkenberg, Oct 27 2011 STATUS approved

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Last modified July 24 05:23 EDT 2021. Contains 346273 sequences. (Running on oeis4.)