A207373 Numbers whose square is the product of a number and its reverse.

252, 403, 504, 660, 816, 2772, 3267, 4356, 20502, 22932, 23632, 25452, 26962, 27972, 31003, 32967, 35143, 41004, 43956, 45864, 48384, 48616, 55242, 58422, 66976, 75525, 225522, 252252, 259952, 279972, 329967, 341033, 403403, 439956, 451044, 504504, 619916

Offset

1,1

Comments

Number and its reverse must have the same number of digits.

Number squared cannot be a palindrome. - Harvey P. Dale, Mar 12 2017

Links

Giovanni Resta, Table of n, a(n) for n = 1..1169 (terms < 10^12, first 90 terms from Harvey P. Dale)

Example

35143^2 = 96721*12769.

Mathematica

nir[n_]:=If[PalindromeQ[n]||Divisible[n, 10], 0, n IntegerReverse[n]]; Sqrt[#] &/@ Select[Array[nir, 500000], #!=0&&IntegerQ[Sqrt[#]]&]//Union (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 12 2017 *)

Crossrefs

Cf. A076750.

Sequence in context: A066695 A372755 A104396 * A072443 A129623 A062904

Adjacent sequences: A207370 A207371 A207372 * A207374 A207375 A207376

Keyword

nonn,base

Author

Carmine Suriano, Feb 17 2012

Status

approved