login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A273363 Numbers n such that the decimal number concat(8,n) is a square. 9
1, 41, 100, 281, 464, 649, 836, 1225, 1796, 2369, 2944, 3521, 4100, 4681, 5264, 5849, 6436, 7025, 7616, 8209, 8804, 9401, 10000, 11801, 13604, 15409, 17216, 19025, 20836, 22649, 24464, 26281, 28100, 29921, 31744, 33569, 35396, 37225 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Elements are squares of integers in [9, sqrt(90)) * sqrt(10)^k without the leading 8 elements for nonnegative k. - David A. Corneth, May 20 2016

LINKS

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

EXAMPLE

41 is a member because 841 = 29^2 is a square.

0 is not a member because 80 is not a square.

MAPLE

t1:=[];

for k from 1 to 50000 do

if issqr(k+8*10^length(k)) then t1:=[op(t1), k]; fi;

od;

t1;

PROG

(PARI) do(n)=my(v=List(), t); for(d=0, n, for(s=sqrtint(81*10^d-1)+1, sqrtint(90*10^d-1), listput(v, s^2-10^d*80))); Vec(v) \\ Charles R Greathouse IV, Nov 26 2016

(MAGMA) [n: n in [1..20000 ] | IsSquare(Seqint(Intseq(n) cat Intseq(8)))]; // Marius A. Burtea, Mar 21 2019

CROSSREFS

Cf. A272671, A273357, A273358, A273359, A273360, A273361, A273362, A273364.

Sequence in context: A260556 A142658 A228573 * A126588 A142794 A225888

Adjacent sequences:  A273360 A273361 A273362 * A273364 A273365 A273366

KEYWORD

nonn,base

AUTHOR

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 18:34 EDT 2019. Contains 322387 sequences. (Running on oeis4.)