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A061457 Numbers n such that n and its reversal are both squares. 7
0, 1, 4, 9, 100, 121, 144, 169, 400, 441, 484, 676, 900, 961, 1089, 9801, 10000, 10201, 10404, 10609, 12100, 12321, 12544, 12769, 14400, 14641, 14884, 16900, 40000, 40401, 40804, 44100, 44521, 44944, 48400, 48841, 67600, 69696, 90000, 90601 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Harry J. Smith, Table of n, a(n) for n=1..1000

EXAMPLE

169 and 961 are both squares.

1089 = 33^2 and 9801 = 99^2 so 1089 and 9801 belong to the sequence.

MATHEMATICA

Select[Range[0, 400]^2, IntegerQ[Sqrt[IntegerReverse[#]]]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 29 2019 *)

PROG

(PARI) { n=0; for (m=0, 1110100, x=m^2; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); if (issquare(r), write("b061457.txt", n++, " ", m^2)) ) } \\ Harry J. Smith, Jul 23 2009

(MAGMA) [n^2: n in [0..306] | IsSquare(Seqint(Reverse(Intseq(n^2))))]; // Bruno Berselli, Apr 30 2011

CROSSREFS

Sequence in context: A245241 A115690 A115689 * A069707 A129967 A182020

Adjacent sequences:  A061454 A061455 A061456 * A061458 A061459 A061460

KEYWORD

nonn,base,easy

AUTHOR

Amarnath Murthy, May 03 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), May 17 2001

STATUS

approved

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Last modified December 6 21:48 EST 2019. Contains 329809 sequences. (Running on oeis4.)