|
Search: id:A062799
|
|
|
| A062799 |
|
Inverse Moebius transform of A001221, the number of distinct prime factors of n. |
|
+0
8
|
|
| 0, 1, 1, 2, 1, 4, 1, 3, 2, 4, 1, 7, 1, 4, 4, 4, 1, 7, 1, 7, 4, 4, 1, 10, 2, 4, 3, 7, 1, 12, 1, 5, 4, 4, 4, 12, 1, 4, 4, 10, 1, 12, 1, 7, 7, 4, 1, 13, 2, 7, 4, 7, 1, 10, 4, 10, 4, 4, 1, 20, 1, 4, 7, 6, 4, 12, 1, 7, 4, 12, 1, 17, 1, 4, 7, 7, 4, 12, 1, 13, 4, 4, 1, 20, 4, 4, 4, 10, 1, 20, 4, 7, 4, 4, 4
(list; graph; listen)
|
|
|
OFFSET
|
1,4
|
|
|
FORMULA
|
a(n)=Sum{A001221[d]}, where d runs over divisors of n.
|
|
EXAMPLE
|
n = 255: divisors = {1, 3, 5, 15, 17, 51, 85, 255}, a(255) = 0+1+1+2+1+2++2+3 = 12
|
|
MATHEMATICA
|
f[n_] := Block[{d = Divisors[n], c = l = 0, k = 2}, l = Length[d]; While[k < l + 1, c = c + Length[ FactorInteger[ d[[k]] ]]; k++ ]; Return[c]]; Table[f[n], {n, 1, 100} ]
|
|
CROSSREFS
|
Cf. A001221.
Sequence in context: A101261 A067614 A113901 this_sequence A063647 A077808 A021471
Adjacent sequences: A062796 A062797 A062798 this_sequence A062800 A062801 A062802
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Labos E. (labos(AT)ana.sote.hu), Jul 19 2001
|
|
|
Search completed in 0.002 seconds
|
