

A089908


Sum of digits of numbers between 0 and (7/9)*(10^n1).


6



0, 28, 609, 9555, 130501, 1654947, 20049393, 235493839, 2704938285, 30549382731, 340493827177, 3754938271623, 41049382716069, 445493827160515, 4804938271604961, 51549382716049407, 550493827160493853
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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) = s(7, n1) where s(a, k)=a*(k+1)+a^2*sum(i=0, k, i*10^(ki))+sum(i=0, k, 5*a*(9*(ki)+a 1)*10^(ki1)).
a(n) = (7*(22*(1+10^n)+9*(4+9*10^n)*n))/162. G.f.: 7*x*(15*x^2x+4) / ((x1)^2*(10*x1)^2).  Colin Barker, Jun 14 2013


CROSSREFS

Cf. A089903, A089904, A089905, A087330, A089906, A089907, A089909, A034967.
Sequence in context: A264459 A004371 A283096 * A038121 A240684 A184329
Adjacent sequences: A089905 A089906 A089907 * A089909 A089910 A089911


KEYWORD

nonn,base,easy


AUTHOR

Benoit Cloitre, Nov 14 2003


STATUS

approved



