OFFSET
1,1
COMMENTS
Partial sums of A095256.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..36
FORMULA
From Andrew Howroyd, Jan 13 2020: (Start)
EXAMPLE
For n = 1; a(1) = 23 because tau (r) of 1-digit numbers r = 1 to 9: {1, 2, 2, 3, 2, 4, 2, 4, 3}. Sum is 23.
PROG
(PARI) \\ too slow for n > 20; here b(n) is A006218(n).
b(n)={sum(k=1, sqrtint(n), n\k)*2 - sqrtint(n)^2}
a(n)={b(10^n-1)-b(10^(n-1)-1)} \\ Andrew Howroyd, Jan 13 2020
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Nov 28 2010
EXTENSIONS
Terms a(11) and beyond from Andrew Howroyd, Jan 13 2020
STATUS
approved