|
Search: id:A089907
|
|
|
| A089907 |
|
Sum of digits of numbers between 0 and (6/9)*(10^n-1). |
|
+0
7
|
|
| 0, 21, 483, 7785, 107787, 1377789, 16777791, 197777793, 2277777795, 25777777797, 287777777799, 3177777777801, 34777777777803, 377777777777805, 4077777777777807, 43777777777777809, 467777777777777811
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
From a suggestion of Yalcin Aktar (aktaryalcin(AT)msn.com)
|
|
FORMULA
|
a(n)=s(6, n-1) where s(a, k)=a*(k+1)+a^2*sum(i=0, k, i*10^(k-i))+sum(i=0, k, 5*a*(9*(k-i)+a- 1)*10^(k-i-1))
|
|
CROSSREFS
|
Cf. A089903, A089904, A089905, A087330, A089906, A089908, A089909, A034967.
Sequence in context: A126996 A025603 A006298 this_sequence A015695 A006299 A065921
Adjacent sequences: A089904 A089905 A089906 this_sequence A089908 A089909 A089910
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 14 2003
|
|
|
Search completed in 0.002 seconds
|
