|
| |
|
|
A025523
|
|
a(n) = 1 + Sum_{ k < n and k | n} a(k).
|
|
0
| |
|
|
1, 2, 3, 5, 6, 9, 10, 14, 16, 19, 20, 28, 29, 32, 35, 43, 44, 52, 53, 61, 64, 67, 68, 88, 90, 93, 97, 105, 106, 119, 120, 136, 139, 142, 145, 171, 172, 175, 178, 198, 199, 212, 213, 221, 229, 232, 233, 281, 283, 291, 294, 302, 303, 323, 326, 346, 349, 352, 353, 397, 398, 401
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Permanent of n X n (0,1) matrix defined by A(i,j)=1 iff j=1 or i divides j. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 05 2003
Partial sums of A074206, ordered factorizations. - Augustine O. Munagi (amunagi(AT)yahoo.com), Jul 10 2007
The subsequence of primes begins: 2, 3, 5, 19, 29, 43, 53, 61, 67, 97, 139, 199, 229, 233, 281, 283, 349, 353, 397, 401. - Jonathan Vos Post (jvospost3(AT)gmail.com)
|
|
|
LINKS
| Herbert S. Wilf, The Redheffer matrix of a partially ordered set, The Electronic Journal of Combinatorics, Volume 11(2), 2004, R#10.
|
|
|
FORMULA
| Running sum of A002033.
a(n) = 1 + Sum_{k = 2 to n} a([n/k]) [From Mitchell Lee (worthawholephan(AT)gmail.com), Jul 26 2010]
|
|
|
CROSSREFS
| Cf. A002321.
Cf. A074206, A002033.
Sequence in context: A092213 A117142 A076061 * A173382 A128689 A116137
Adjacent sequences: A025520 A025521 A025522 * A025524 A025525 A025526
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
|
| |
|
|
