A066618 Both m and its reverse are one more than a square and m does not end in 0.

1, 2, 5, 101, 626, 5477, 7745, 10001, 1000001, 1010026, 1040401, 2217122, 2676497, 5053505, 6200101, 7946762, 100000001, 101808101, 10000000001, 10180608202, 10182828101, 10408080401, 20280608101, 26573890226, 26995147205

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..53

Example

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

Mathematica

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]]]

Prog

(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

Crossrefs

Sequence in context: A120800 A376942 A277341 * A027720 A132482 A208209

Adjacent sequences: A066615 A066616 A066617 * A066619 A066620 A066621

Keyword

nonn,base

Author

Erich Friedman, Jan 08 2002

Status

approved