OFFSET
1,1
COMMENTS
a(78) is the last term, as none of the candidates for a(79) is prime. - Giovanni Resta, Sep 20 2019
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..78
MAPLE
cp:= proc(x, y) if x[1] < y[1] then true
elif x[1] > y[1] then false
elif nops(x)=1 then true
else procname(x[2..-1], y[2..-1])
fi
end proc: A[1]:= 5: L:= [5]:
for n from 2 to 15 do
nL:= nops(L);
Lp:= sort([seq(seq([op(L[1..i]), x, op(L[i+1..-1])], x=`if`(i=0, 1..9, 0..9)), i=0..nL)], cp);
cands:= map(t -> add(t[i]*(10^(i-1)+10^(2*nL+1-i)), i=1..nL)+t[nL+1]*10^(nL), Lp);
found:= false;
for i from 1 to nops(cands) do
if isprime(cands[i]) then
A[n]:= cands[i];
L:= Lp[i];
found:= true;
break
fi
od;
if not found then break fi
od:
seq(A[i], i=1..15); # Robert Israel, Jan 03 2017, corrected Sep 20 2019
CROSSREFS
KEYWORD
base,fini,full,nonn
AUTHOR
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Apr 29 2003
EXTENSIONS
Terms after a(4) corrected by Giovanni Resta, Sep 20 2019
STATUS
approved