A114765 a(n) = floor(sqrt(7) * 10^n)^2.

4, 676, 69696, 6996025, 699972849, 69999930625, 6999998354001, 699999994145169, 69999999943667161, 6999999999658218721, 699999999965821872100, 69999999999757088783236, 6999999999996874888812096, 699999999999952064012316025, 69999999999999968753591518681

Offset: 0

Author

Amarnath Murthy, Nov 17 2005

Keywords

• nonn

Comments

Largest square less than 7 * 10^(2n).

Examples

			sqrt(7) = 2.645751311...
floor(sqrt(7) * 10) = 26 and 26^2 = 676, so a(1) = 676.
floor(sqrt(7) * 100) = 264 and 264^2 = 69696, so a(2) = 69696.
floor(sqrt(7) * 1000) = 2645 and 2645^2 = 6996025, so a(3) = 6996025.
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..100

Crossrefs

Cf. A114761, A114762, A114763, A114764.

Cf. A010465 (sqrt(7)).

Programs

Magma

[Floor(7^(1/2)*10^n)^2: n in [0..150]]; // Vincenzo Librandi, Feb 05 2011

Mathematica

$MaxExtraPrecision := 200; Table[Floor[7^(1/2) * 10^n]^2, {n, 0, 20}] (* Stefan Steinerberger, Jan 26 2006 *)

PARI

a(n)={sqrtint(7*10^(2*n))^2} \\ Andrew Howroyd, Nov 09 2019

Extensions

More terms from Stefan Steinerberger, Jan 26 2006

Terms a(12) and beyond from Andrew Howroyd, Nov 09 2019