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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
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
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
Sequence in context: A162016 A242040 A206822 * A334457 A010456 A072496
KEYWORD
nonn,easy
AUTHOR
J. W. Helkenberg, Oct 27 2011
STATUS
approved