|
| |
|
|
A124052
|
|
Sum from 1 to n of all factors of primes less than n such that the power of any factor (p) never exceeds log(n) base p.
|
|
0
| |
|
|
1, 3, 12, 28, 168, 168, 1344, 2880, 9360, 9360, 112320, 112320, 1572480, 1572480, 1572480, 3249792, 58496256, 58496256, 1169925120, 1169925120, 1169925120, 1169925120, 28078202880, 28078202880, 145070714880, 145070714880
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| a(n) > a(n-1) implies n is either a prime or the power of a prime.
|
|
|
FORMULA
| a(n) = a(n-1)(1+n*(P-1)/(n-1)) ( If n is the power of any prime (P) ) a(n) = A(n-1) If n is not the power of any prime
|
|
|
EXAMPLE
| A(5) = A(6) = (1+2+4)(1+3)(1+5) = 1 + 2 + 3 + 4 + 5 + 6 + 10 + 12 + 15 + 20 + 30 + 60
|
|
|
CROSSREFS
| Sequence in context: A005995 A034503 A026557 * A104353 A001860 A199035
Adjacent sequences: A124049 A124050 A124051 * A124053 A124054 A124055
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Timothy Frison (frison(AT)gmail.com), Nov 03 2006
|
| |
|
|
