OFFSET
1,1
EXAMPLE
a(5) = 15131197 is a prime and a concatenation of 15,13,11,9 and 7.
MAPLE
for n from 1 to 32 do d := 0:c := true: if((n mod 3)=0) then c := false:a := 0:end if: while(c=true) do a := 2*(n+d)-1:for j from 1 to n-1 do a := 2*(n+d-j)-1+10^( floor(evalf(log(2*(n+d-j)-1)/log(10))+0.0000000001 )+1)*a:end do: if(isprime(a))then c := false:end if:d := d+1:end do:b[n] := a:end do:seq(b[h], h=1..32);
CROSSREFS
KEYWORD
base,hard,nonn
AUTHOR
Amarnath Murthy, Mar 04 2002
EXTENSIONS
More terms from Sascha Kurz, Mar 27 2002
Definition clarified by Harvey P. Dale, Dec 25 2022
STATUS
approved