|
| |
|
|
A097979
|
|
Total number of largest parts in all compositions of n.
|
|
1
| |
|
|
1, 3, 6, 12, 23, 46, 91, 183, 367, 737, 1478, 2962, 5928, 11858, 23707, 47384, 94698, 189260, 378277, 756160, 1511730, 3022672, 6044472, 12088395, 24177600, 48359695, 96732370, 193495606, 387057584, 774248858, 1548754115, 3097980230
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Also number of compositions of n+1 with unique largest part. - Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 03 2005
|
|
|
FORMULA
| G.f.: (1-x)^2*Sum(x^k/(1-2*x+x^(k+1))^2, k=1..infinity).
|
|
|
PROG
| (PARI) { b(t)=local(r); sum(k=1, t, forstep(s=t%k, t-k, k, u=(t-k-s)\k; r+=binomial(-2, s)*(-2)^(s-u)*binomial(s, u))); r } { a(n)=b(n)-2*b(n-1)+b(n-2) } (Alekseyev)
|
|
|
CROSSREFS
| Cf. A097941, A046746.
Sequence in context: A050243 A024505 A005256 * A173216 A003204 A038620
Adjacent sequences: A097976 A097977 A097978 * A097980 A097981 A097982
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 07 2004
|
|
|
EXTENSIONS
| More terms from Max Alekseyev (maxale(AT)gmail.com), Apr 16 2005
|
| |
|
|
