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A160955
a(n+1) is the largest prime formed by appending a single digit to a(n); a(1)=18.
2
18, 181, 1811, 18119, 181199, 1811993
OFFSET
1,1
COMMENTS
There is no prime a(7) since 18119930 to 18119939 are all composite.
EXAMPLE
a(1)=18,
a(2)=181,
a(3)=1811,
a(4)=18119,
a(5)=181199,
a(6)=1811993. [Corrected by Jon E. Schoenfield, Feb 18 2019]
MAPLE
A160955 :=proc(n) option remember ; local d; if n =1 then 18; else for d from 1 to 9 by 2 do if isprime(10*prochame n+d) then RETURN(10*procnam n+d 0 ; fi; end:
seq(A160955(n), n=1..10) ; # R. J. Mathar, May 26 2009
CROSSREFS
KEYWORD
nonn,base,easy,fini,full
AUTHOR
EXTENSIONS
Redundant part of the definition removed by R. J. Mathar, May 21 2010
STATUS
approved