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A273358 Numbers n such that the decimal number concat(3,n) is a square. 8
6, 24, 61, 136, 249, 364, 481, 600, 721, 844, 969, 1329, 1684, 2041, 2400, 2761, 3124, 3489, 3856, 4225, 4596, 4969, 5344, 5721, 6100, 6481, 6864, 7249, 7636, 8025, 8416, 8809, 9204, 9601, 10249, 11364, 12481, 13600, 14721, 15844, 16969, 18096 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Elements are squares of integers in (sqrt(31), sqrt(40)) * sqrt(10)^k without the leading 3 elements for nonnegative k. - David A. Corneth, May 20 2016

LINKS

Nathan Fox, Table of n, a(n) for n = 1..11067

EXAMPLE

61 is a member because 361 = 19^2 is a square.

0 is not a member because 30 is not a square.

MAPLE

t1:=[];

for k from 1 to 20000 do

if issqr(k+3*10^length(k)) then t1:=[op(t1), k]; fi;

od;

t1;

CROSSREFS

Cf. A272671, A273357, A273359, A273360, A273361, A273362, A273363, A273364.

Sequence in context: A292889 A272951 A101854 * A101877 A270851 A092348

Adjacent sequences:  A273355 A273356 A273357 * A273359 A273360 A273361

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 19 11:29 EDT 2019. Contains 321329 sequences. (Running on oeis4.)