A099671 Partial sums of repdigits of A002278.

4, 48, 492, 4936, 49380, 493824, 4938268, 49382712, 493827156, 4938271600, 49382716044, 493827160488, 4938271604932, 49382716049376, 493827160493820, 4938271604938264, 49382716049382708, 493827160493827152, 4938271604938271596, 49382716049382716040, 493827160493827160484

Offset: 1

Author

Labos Elemer, Nov 17 2004

Keywords

• base
• nonn
• easy

Examples

			4 + 44 + 444 + 4444 + 44444 = a(5) = 49380.
		

Links

• Index entries for linear recurrences with constant coefficients, signature (12,-21,10).

Crossrefs

Cf. A002275-A002283, A014824, A057932.

Programs

Mathematica

<Robert G. Wilson v, Nov 20 2004 *)

Formula

a(n) = (4/81)*(10^(n+1) - 9*n - 10). - R. Piyo (nagoya314(AT)yahoo.com), Dec 10 2004

From Chai Wah Wu, Feb 28 2018: (Start)

a(n) = 12*a(n-1) - 21*a(n-2) + 10*a(n-3) for n > 3.

G.f.: 4*x/((1 - x)^2*(1 - 10*x)). (End)

From Elmo R. Oliveira, Apr 03 2025: (Start)

E.g.f.: 4*exp(x)*(10*exp(9*x) - 9*x - 10)/81.

a(n) = 4*A014824(n). (End)

Extensions

More terms from Elmo R. Oliveira, Apr 03 2025