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A196000 Numbers k such that 90*k + 19 is prime. 21
0, 1, 2, 4, 8, 9, 10, 11, 14, 16, 17, 22, 23, 24, 25, 28, 30, 34, 35, 36, 39, 41, 43, 46, 48, 50, 53, 55, 56, 60, 63, 64, 65, 69, 74, 77, 78, 79, 80, 81, 83, 85, 86, 91, 93, 98, 99, 101, 102, 107, 108, 109, 111, 112, 115, 116 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

A142322 is a digital root 1 and last digit 9 preserving sequence.

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = (A142322(n) - 19)/90.

MAPLE

A142322 := proc(n)

        option remember;

        if n = 1 then

                19 ;

        else

                a := nextprime(procname(n-1)) ;

                while (a mod 45) <> 19 do

                        a := nextprime(a) ;

                end do;

                return a;

        end if;

end proc:

A196000 := proc(n)

        (A142322(n)-19)/90 ;

end proc:

seq(A196000(n), n=1..80) ; # R. J. Mathar, Oct 31 2011

MATHEMATICA

Select[Range[0, 120], PrimeQ[90 # + 19] &] (* Ivan Neretin, Apr 27 2017 *)

PROG

(PARI) is(n)=isprime(90*n+19) \\ Charles R Greathouse IV, Apr 25 2016

CROSSREFS

Cf. A195953, A181732, A198382.

Sequence in context: A255908 A011402 A131625 * A044952 A047466 A003485

Adjacent sequences:  A195997 A195998 A195999 * A196001 A196002 A196003

KEYWORD

nonn,easy

AUTHOR

J. W. Helkenberg, Oct 27 2011

STATUS

approved

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Last modified July 13 13:48 EDT 2020. Contains 335688 sequences. (Running on oeis4.)