A177096 a(n) = 5*(10^n - 2).

40, 490, 4990, 49990, 499990, 4999990, 49999990, 499999990, 4999999990, 49999999990, 499999999990, 4999999999990, 49999999999990, 499999999999990, 4999999999999990, 49999999999999990, 499999999999999990, 4999999999999999990, 49999999999999999990, 499999999999999999990

Offset: 1

Author

Vincenzo Librandi

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (11,-10).

Crossrefs

Cf. A099150, A198971.

Programs

PARI

Vec(10*x*(4+5*x)/(10*x^2-11*x+1) + O(x^21)) \\ Elmo R. Oliveira, May 02 2025

Formula

G.f.: 10*x*(4+5*x)/((10*x-1)*(x-1)). - R. J. Mathar, Jan 06 2011

From Elmo R. Oliveira, May 02 2025: (Start)

E.g.f.: 5*(1 + exp(10*x) - 2*exp(x)).

a(n) = 5*A099150(n) = 10*A198971(n-1).

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

Extensions

More terms from Elmo R. Oliveira, May 02 2025