A032343 a(n) = 10*a(n-1)+n^2, a(0)=0.

0, 1, 14, 149, 1506, 15085, 150886, 1508909, 15089154, 150891621, 1508916310, 15089163221, 150891632354, 1508916323709, 15089163237286, 150891632373085, 1508916323731106, 15089163237311349, 150891632373113814

Offset

0,3

Comments

a(n)/10^n converges to 110/729=0.15089163237311...

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Formula

a(n) =(10^n-1)*(110/729)-n^2/9-n*(20/81).

G.f.: (x^2+x)/((x-1)^3*(10*x-1)). - Harvey P. Dale, Mar 20 2011

Mathematica

CoefficientList[Series[(x^2+x)/((x-1)^3 (10x-1)), {x, 0, 30}], x]  (* Harvey P. Dale, Mar 20 2011 *)
RecurrenceTable[{a[0] == 0, a[n] == 10*a[n-1] + n^2}, a, {n, 100}] (* Vincenzo Librandi, Mar 10 2013 *)

Prog

(Magma) [0] cat [n le 1 select n else 10*Self(n-1)+n^2: n in [1..20]]; // Vincenzo Librandi, Mar 10 2013

Crossrefs

Cf. A014824, A019521.

Sequence in context: A162965 A067103 A081184 * A222614 A019521 A009614

Adjacent sequences: A032340 A032341 A032342 * A032344 A032345 A032346

Keyword

nonn,easy

Author

Henry Bottomley, Jul 04 2000

Status

approved