A023113 Squares that remain square when the digit 6 is appended.

1, 25, 1849, 36481, 2666689, 52606009, 3845364121, 75857828929, 5545012396225, 109386936710041, 7995904029992761, 157735886878050625, 11530088066237165569, 227455039491212291641, 16626378995609962758169

Offset

1,2

Comments

The terms of the sequence are the squares of the y-values in the solution to the Pellian equation x^2-10*y^2=6. - Colin Barker, Sep 28 2013

Links

Table of n, a(n) for n=1..15.

Formula

Empirical g.f.: -x*(x^4+24*x^3+382*x^2+24*x+1) / ((x-1)*(x^2-38*x+1)*(x^2+38*x+1)). - Colin Barker, Jan 31 2013

Crossrefs

Cf. A023111, A023112, A023114.

Sequence in context: A187404 A370436 A172261 * A322247 A177837 A056047

Adjacent sequences: A023110 A023111 A023112 * A023114 A023115 A023116

Keyword

nonn,base

Author

David W. Wilson

Extensions

Definition modified by Harvey P. Dale, Sep 08 2019

Status

approved