|
Search: id:A096825
|
|
|
| A096825 |
|
Maximal size of an antichain in divisor lattice D(n). |
|
+0
3
|
|
| 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 3, 1, 1, 2, 2, 2, 3, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 4, 1, 2, 2, 1, 2, 3, 1, 2, 2, 3, 1, 3, 1, 2, 2, 2, 2, 3, 1, 2, 1, 2, 1, 4, 2, 2, 2, 2, 1, 4, 2, 2, 2, 2, 2, 2, 1, 2, 2, 3
(list; graph; listen)
|
|
|
OFFSET
|
1,6
|
|
|
COMMENT
|
The divisor lattice D(n) is the lattice of the divisors of the natural number n.
|
|
FORMULA
|
a(n) is the coefficient at x^k in (1+x+...+x^k_1)*...*(1+x+...+x^k_q) where n=p_1^k_1*...*p_q^k_q is the prime factorization of n and k=floor((k_1+...+k_q)/2). - Alec Mihailovs (alec(AT)mihailovs.com), Aug 22 2004
|
|
MAPLE
|
a:=proc(n) local klist, x; klist:=ifactors(n)[2, 1..-1, 2]; coeff(normal(mul((1-x^(k+1))/(1-x), k=klist)), x, floor(add(k, k=klist)/2)) end: seq(a(n), n=1..100);
|
|
CROSSREFS
|
Cf. A096826, A096827.
Sequence in context: A079553 A001221 A064372 this_sequence A007875 A050320 A121382
Adjacent sequences: A096822 A096823 A096824 this_sequence A096826 A096827 A096828
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Yuval Dekel (dekelyuval(AT)hotmail.com) and Vladeta Jovovic (vladeta(AT)Eunet.yu), Aug 17 2004
|
|
EXTENSIONS
|
More terms from Alec Mihailovs (alec(AT)mihailovs.com), Aug 22 2004
|
|
|
Search completed in 0.002 seconds
|
