%I #8 May 04 2019 21:08:07

%S 7,97,983,9941,99839,999983,9998239,99999989,999950881,9999999929,

%T 99999999833,999999999989,9999999999863,99999999999971,

%U 999999961946087,9999999999999917,99999999989350667,999999999999999989

%N Last prime subtrahend at 10^n in A146757.

%e A(2)=97 because 97 is the 15th and last prime difference under 10^2.

%p A146758 := proc(n) local p: p:=10^n: do p:=prevprime(p): if(isprime(ceil(evalf(sqrt(p)))^2-p))then return p: fi: od: end: seq(A146758(n),n=1..14); # _Nathaniel Johnston_, Oct 01 2011

%o (UBASIC) 10 'sq less pr are prime 20 N=1:O=1:C=1 30 A=3:S=sqrt(N):if N>10^3 then print N,C-1:stop 40 B=N\A 50 if B*A=N then 100 60 A=A+2 70 if A<=S then 40 80 R=O^2:Q=R-N 90 if N<R and N=prmdiv(N) and Q=prmdiv(Q) then if Q>1 print R;N;Q;C:N=N+2:C=C+1:goto 30 100 N=N+2:if N<R then 30:else O=O+1:goto 80

%Y Cf. A146757, A146759, A146760.

%K more,nonn

%O 1,1

%A _Enoch Haga_, Nov 02 2008

%E a(8)-a(18) from _Nathaniel Johnston_, Oct 01 2011