login
A099675
Partial sums of repdigits of A002282.
4
8, 96, 984, 9872, 98760, 987648, 9876536, 98765424, 987654312, 9876543200, 98765432088, 987654320976, 9876543209864, 98765432098752, 987654320987640, 9876543209876528, 98765432098765416, 987654320987654304
OFFSET
1,1
FORMULA
a(n) = (8/81)*(10^(n+1) - 9*n - 10). - R. Piyo (nagoya314(AT)yahoo.com), Dec 10 2004
a(n) = 12*a(n-1) - 21*a(n-2) + 10*a(n-3). - Wesley Ivan Hurt, Jan 20 2024
EXAMPLE
8 + 88 + 888 + 8888 + 88888 = a(5) = 98760.
MATHEMATICA
<<NumberTheory`NumberTheoryFunctions` Table[{k, Table[Apply[Plus, Table[k*(10^n-1)/9, {n, 1, m}]], {m, 1, 35}]}, {k, 1, 9}]
Table[8/9*Sum[10^i - 1, {i, n}], {n, 18}] (* Robert G. Wilson v, Nov 20 2004 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Labos Elemer, Nov 17 2004
STATUS
approved