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%I #8 Jan 31 2019 19:38:16
%S 2,5,11,101,313,727,10301,19891,30103,70207,1003001,1936391,3001003,
%T 7014107,100030001,193191391,300020003,700020007,10000500001,
%U 19301110391,30000500003,70005450007,1000008000001,1930022200391,3000002000003,7000005000007,100000323000001
%N Palindromic primes with successive increasing difference: a(k)-a(k-1) < a(k+1)- a(k).
%H Robert Israel, <a href="/A078790/b078790.txt">Table of n, a(n) for n = 1..1600</a>
%p revdigs:= proc(x) local F,i;
%p F:= convert(x,base,10);
%p add(F[-i]*10^(i-1),i=1..nops(F))
%p end proc:
%p f1:= proc(n)
%p local m0, a0,b0,m,a,b,c,x;
%p m0:= ilog10(n)+1;
%p if m0::even then m:= m0/2+1; a0:= 1; b0:= 0;
%p else a0:= floor(n/10^(m0-1));
%p if a0 = 4 or a0 = 5 then a0:= 7; b0:= 0
%p elif a0::odd then b0:= n - 10^(m0-1)*a0;
%p else a0:= a0+1; b0:= 0;
%p fi;
%p m:= ceil(m0/2); b0:= floor(b0/10^(m-1));
%p fi;
%p for a from a0 to 9 by 2 do
%p for b from b0 to 10^(m-1) do
%p x:= 10^(m-1)*a + b;
%p x:= 10^(m-1)*x + revdigs(floor(x/10));
%p if x < n then next fi;
%p if isprime(x) then return x fi
%p od;
%p b0:= 0;
%p od;
%p procname(10^m0);
%p end proc;
%p A[1]:= 2: A[2]:= 5: A[3]:= 11:
%p for n from 4 to 30 do
%p A[n]:= f1(2*A[n-1]-A[n-2]+1);
%p od:
%p seq(A[i],i=1..30); # _Robert Israel_, Jan 31 2019
%t p = 1; d = 0; Do[ q = FromDigits[ Join[ IntegerDigits[n], Drop[ Reverse[ IntegerDigits[n]], 1]]]; If[ PrimeQ[q] && q - p > d, Print[q]; d = q - p; p = q], {n, 2, 3000002}]
%Y Cf. A071250.
%K base,nonn
%O 1,1
%A _Robert G. Wilson v_, Dec 03 2002
%E Corrected by _T. D. Noe_, Oct 25 2006
%E Corrected and more terms from _Robert Israel_, Jan 31 2019
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