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
KEYWORD
nonn,easy
AUTHOR
J. W. Helkenberg, Oct 27 2011
STATUS
approved