A069707 Squares with property that swapping first and last digits also gives a square.

1, 4, 9, 100, 121, 144, 169, 400, 441, 484, 676, 900, 961, 1521, 1681, 1764, 4624, 4761, 5625, 9409, 10000, 10201, 10404, 10609, 11881, 12321, 14161, 14641, 16641, 17161, 19321, 19881, 40000, 40401, 40804, 41209, 43264, 44944, 47524, 49284

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

1764 and 4761 both are squares hence both are members.

Mathematica

Do[t = IntegerDigits[n^2]; u = t; u[[1]] = t[[ -1]]; u[[ -1]] = t[[1]]; t = FromDigits[u]; If[ IntegerQ[ Sqrt[t]], Print[n^2]], {n, 1, 300}]
sfldQ[n_]:=Module[{idn=IntegerDigits[n]}, IntegerQ[Sqrt[FromDigits[Join[ {idn[[-1]]}, Most[ Rest[idn]], {idn[[1]]}]]]]]; Join[{1, 4, 9}, Select[ Range[10, 250]^2, sfldQ]] (* Harvey P. Dale, Oct 13 2020 *)

Crossrefs

Cf. A069706, A069708.

Sequence in context: A115690 A115689 A061457 * A129967 A182020 A087553

Adjacent sequences: A069704 A069705 A069706 * A069708 A069709 A069710

Keyword

nonn,base

Author

Amarnath Murthy, Apr 08 2002

Extensions

Edited and extended by Robert G. Wilson v

Edited by N. J. A. Sloane, Jan 20 2009

Status

approved