A171510 a(n) = 10*a(n-1) + a(n-2), with a(1)=2 and a(2)=1.

2, 1, 12, 121, 1222, 12341, 124632, 1258661, 12711242, 128371081, 1296422052, 13092591601, 132222338062, 1335315972221, 13485382060272, 136189136574941, 1375376747809682, 13889956614671761, 140274942894527292, 1416639385559944681, 14306668798493974102

Offset: 1

Author

Mark Dols, Dec 10 2009

Keywords

• nonn
• easy

Links

• Colin Barker, Table of n, a(n) for n = 1..997
• Index entries for linear recurrences with constant coefficients, signature (10,1).

Crossrefs

Cf. A015456, A065941.

Programs

Mathematica

RecurrenceTable[{a[n] == 10 a[n - 1] + a[n - 2], a[1] == 2, a[2] == 1}, a, {n, 1, 21}] (* or *) LinearRecurrence[{10, 1}, {2, 1}, 21] (* Michael De Vlieger, Oct 02 2015 *)

PARI

Vec(x*(19*x-2)/(x^2+10*x-1) + O(x^40)) \\ Colin Barker, Oct 02 2015

Formula

G.f.: x*(19*x-2) / (x^2+10*x-1). - Colin Barker, Oct 02 2015