A068617 Starting from a(1)=8, each subsequent term is the minimal square obtained by inserting at least one digit in the previous term.

8, 81, 841, 38416, 3841600, 384160000, 38416000000, 3841600000000, 384160000000000, 38416000000000000, 3841600000000000000, 384160000000000000000, 38416000000000000000000

Offset

1,1

Comments

The growing square sequence for 1 and 6, 2 and 5, 4 and 9 in pairs are the same.

Links

Table of n, a(n) for n=1..13.

Index entries for linear recurrences with constant coefficients, signature (100).

Formula

For n>=4, a(n) = 38416*100^(n-4).

From Chai Wah Wu, Aug 03 2020: (Start)

a(n) = 100*a(n-1) for n > 4.

G.f.: x*(45684*x^3 + 7259*x^2 + 719*x - 8)/(100*x - 1). (End)

Example

a(2)=81 hence a(3) = 841 the smallest square formed from 81.

Crossrefs

Cf. A068175, A068176, A068177, A068178, A068616.

Sequence in context: A098308 A055996 A324016 * A207994 A210127 A007778

Adjacent sequences: A068614 A068615 A068616 * A068618 A068619 A068620

Keyword

base,nonn

Author

Amarnath Murthy, Feb 25 2002

Extensions

More terms from Sean A. Irvine, Sep 24 2009

Edited and extended by Max Alekseyev, Oct 12 2009

Status

approved