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A273364 Numbers n such that the decimal number concat(9,n) is a square. 8
61, 216, 409, 604, 801, 1204, 1809, 2416, 3025, 3636, 4249, 4864, 5481, 6100, 6721, 7344, 7969, 8596, 9225, 9856, 10116, 12025, 13936, 15849, 17764, 19681, 21600, 23521, 25444, 27369, 29296, 31225, 33156, 35089, 37024, 38961, 40900, 42841, 44784 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Elements are squares of integers in (sqrt(91), 10) * sqrt(10)^k without the leading 9 elements for nonnegative k. - David A. Corneth, May 20 2016

LINKS

Nathan Fox, Table of n, a(n) for n = 1..10000

EXAMPLE

61 is a member because 961 = 31^2 is a square.

0 is not a member because 90 is not a square.

MAPLE

t1:=[];

for k from 1 to 50000 do

if issqr(k+9*10^length(k)) then t1:=[op(t1), k]; fi;

od;

t1;

CROSSREFS

Cf. A272671, A273357, A273358, A273359, A273360, A273361, A273362, A273363.

Sequence in context: A234925 A171585 A038643 * A297731 A228130 A142267

Adjacent sequences:  A273361 A273362 A273363 * A273365 A273366 A273367

KEYWORD

nonn,base

AUTHOR

Nathan Fox, Brooke Logan, and N. J. A. Sloane, May 20 2016

STATUS

approved

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Last modified March 24 19:42 EDT 2019. Contains 321448 sequences. (Running on oeis4.)