A066618 - OEIS

%I #14 May 24 2017 11:40:19

%S 1,2,5,101,626,5477,7745,10001,1000001,1010026,1040401,2217122,

%T 2676497,5053505,6200101,7946762,100000001,101808101,10000000001,

%U 10180608202,10182828101,10408080401,20280608101,26573890226,26995147205

%N Both m and its reverse are one more than a square and m does not end in 0.

%H Harry J. Smith, <a href="/A066618/b066618.txt">Table of n, a(n) for n = 1..53</a>

%e 7745 = 88^2 + 1 and 5477 = 74^2 + 1.

%t dtn[L_] := Fold[10#1+#2&, 0, L] A={}; For[i=1, i>0, i++, t=dtn[Reverse[IntegerDigits[i^2+1]]]; If[IntegerQ[(t-1)^(1/2)]&&Mod[i^2, 10]=!=9, AppendTo[A, i^2+1]; Print[A]]]

%o (PARI) Rev(x)= { local(d, r=0); while (x>0, d=x%10; x\=10; r=r*10 + d); return(r) } { n=0; for (m=0, 10^10, k=m^2 + 1; if (k%10 && issquare(Rev(k) - 1), write("b066618.txt", n++, " ", k); if (n==100, return)) ) } \\ _Harry J. Smith_, Mar 13 2010

%K nonn,base

%O 1,2

%A _Erich Friedman_, Jan 08 2002