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A167045 Squares that remains a square when some single digit is inserted in front of its decimal expansion. 1

%I #12 Jul 19 2016 16:54:58

%S 1,4,9,25,100,225,400,625,900,1225,2025,2500,3025,4225,5625,7225,

%T 10000,22500,30625,40000,50625,62500,70225,75625,90000,93025,122500,

%U 202500,250000,302500,330625,422500,455625,562500,722500,765625,950625,1000000

%N Squares that remains a square when some single digit is inserted in front of its decimal expansion.

%H Chai Wah Wu, <a href="/A167045/b167045.txt">Table of n, a(n) for n = 1..1000</a>

%F Union of A167035, A167036, A167037, A167038, A167039, A167041, A167042, A167043 and A167044. [_R. J. Mathar_, Oct 30 2009]

%e 225 is in the sequence because both 225 and 1225 are squares.

%p a := proc (n) local s, c, j: s := proc (n) options operator, arrow: nops(convert(n, base, 10)) end proc: c := 0: for j to 9 do if type(sqrt(j*10^s(n^2)+n^2), integer) = true then c := c+1 else end if end do: if 0 < c then n^2 else end if end proc: seq(a(n), n = 1 .. 1200); # _Emeric Deutsch_, Nov 01 2009

%t srsQ[n_]:=AnyTrue[Range[9]*10^IntegerLength[n]+n,IntegerQ[Sqrt[#]]&]; Select[ Range[1200]^2,srsQ] (* The program uses the AnyTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jul 19 2016 *)

%K nonn,base

%O 1,2

%A _Claudio Meller_, Oct 27 2009

%E Edited by _N. J. A. Sloane_, Oct 29 2009

%E More terms from _R. J. Mathar_ and _Emeric Deutsch_, Oct 30 2009

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Last modified May 3 00:26 EDT 2024. Contains 372203 sequences. (Running on oeis4.)