A249633 Numbers whose squares remain squares when prepended with 1 and appended with 25 in base 10.

285290, 37501930, 5986235584, 6402200716, 7097946940, 2189113296470, 533822715205534, 120542200191255266, 175167560462651234, 1035777761966641262300, 55811056504696202088334, 87383897508158263975600, 342433449090893699643070, 356558269841736892522930

Offset

1,1

Comments

Square roots of A249621.

a(34) >= 10^50. - Hiroaki Yamanouchi, Nov 22 2014

a(34) = 3894512793630238968387948459831502376753914222969510. - Giovanni Resta, Mar 08 2017

Links

Chai Wah Wu and Hiroaki Yamanouchi, Table of n, a(n) for n = 1..33 (terms a(1)-a(27) from Chai Wah Wu)

Example

81390384100 = 285290^2 and 18139038410025 = 4258995^2.

Mathematica

a249633Q[n_Integer] :=
  Module[{m, t}, m := ToString[n^2];
   IntegerQ[Sqrt[ToExpression["1" <> m <> "25"]]]]; Select[Range[300000], a249633Q[#] &] (* Michael De Vlieger, Nov 06 2014 *)

Crossrefs

Cf. A249621.

Sequence in context: A214357 A096519 A334311 * A157112 A272444 A250824

Adjacent sequences: A249630 A249631 A249632 * A249634 A249635 A249636

Keyword

nonn,base

Author

Chai Wah Wu, Nov 02 2014

Status

approved