A087330 Sum of all digits of all integers less than or equal to 555...55 (with n 5's) in base 10.

0, 15, 370, 6150, 86430, 1114210, 13641990, 161419770, 1864197550, 21141975330, 236419753110, 2614197530890, 28641975308670, 311419753086450, 3364197530864230, 36141975308642010, 386419753086419790

Offset

0,2

Comments

From a suggestion of Yalcin Aktar

Links

Table of n, a(n) for n=0..16.

Index entries for linear recurrences with constant coefficients, signature (22,-141,220,-100).

Formula

a(n) = 20/9*n-110/81*10^n+110/81+5/2*n*10^n (formula from B. Greco).

G.f.: 5*x*(25*x^2+8*x+3) / ((x-1)^2*(10*x-1)^2). - Colin Barker, Jun 14 2013

Example

a(1)=15 since numbers less than or equal to 5 are 1,2,3,4,5 and the sum of digits is 1+2+3+4+5=15.

Mathematica

LinearRecurrence[{22, -141, 220, -100}, {0, 15, 370, 6150}, 20] (* Harvey P. Dale, Aug 01 2016 *)

Crossrefs

Sequence in context: A240197 A012486 A035020 * A035274 A324415 A145409

Adjacent sequences: A087327 A087328 A087329 * A087331 A087332 A087333

Keyword

base,nonn,easy

Author

Benoit Cloitre, Oct 20 2003

Status

approved