A086942 Integers k such that R(k+8) = 4.

32, 392, 3992, 39992, 399992, 3999992, 39999992, 399999992, 3999999992, 39999999992, 399999999992, 3999999999992, 39999999999992, 399999999999992, 3999999999999992, 39999999999999992, 399999999999999992, 3999999999999999992, 39999999999999999992

Offset: 1

Author

Ray Chandler, Jul 24 2003

Keywords

• nonn
• base
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..300
• Index entries for linear recurrences with constant coefficients, signature (11,-10).

Crossrefs

Cf. A004086, A086940, A086943, A099150, A198971.

Programs

Magma

[4*10^n-8: n in [1..25]]; // Vincenzo Librandi, Aug 22 2011

Mathematica

4*10^Range[20] - 8 (* Paolo Xausa, Sep 21 2024 *)

Formula

a(n) = 4*10^n - 8.

R(a(n)) = A086943(n).

G.f.: 8*x*(5*x+4)/((10*x-1)*(x-1)).

a(n) = 8*A198971(n-1).

From Elmo R. Oliveira, May 01 2025: (Start)

E.g.f.: 4*(1 - 2*exp(x) + exp(10*x)).

a(n) = 4*A099150(n) = 2*A086940(n).

a(n) = 11*a(n-1) - 10*a(n-2) for n > 2. (End)