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A249633 Numbers whose squares remain squares when prepended with 1 and appended with 25 in base 10. 4
285290, 37501930, 5986235584, 6402200716, 7097946940, 2189113296470, 533822715205534, 120542200191255266, 175167560462651234, 1035777761966641262300, 55811056504696202088334, 87383897508158263975600, 342433449090893699643070, 356558269841736892522930 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 7 14:09 EDT 2021. Contains 343650 sequences. (Running on oeis4.)