|
| |
|
|
A141118
|
|
G.f. A(x) satisfies: A(A(A(x))) = x + 9*x^2.
|
|
2
| |
|
|
1, 3, -18, 189, -2430, 34020, -486972, 6786261, -86946372, 919825956, -5269375296, -80180038944, 3575424508272, -77211406919844, 1164244485947400, -12342809241883386, 102419678663170128, -2040575112980362980
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
EXAMPLE
| G.f.: A(x) = x + 3*x^2 - 18*x^3 + 189*x^4 - 2430*x^5 + 34020*x^6 -+...
A(A(x)) = x + 6*x^2 - 18*x^3 + 135*x^4 - 1296*x^5 + 13122*x^6 -+...
|
|
|
PROG
| (PARI) {a(n, m=3)=local(F=x+m*x^2+x*O(x^n), G); if(n<1, 0, for(k=3, n, G=F+x*O(x^k); for(i=1, m-1, G=subst(F, x, G)); F=F+((-polcoeff(G, k))/m)*x^k); return(polcoeff(F, n, x)))}
|
|
|
CROSSREFS
| Cf. A027436, A141119, A141120, A141121.
Sequence in context: A006472 A132853 A084879 * A033030 A178014 A002824
Adjacent sequences: A141115 A141116 A141117 * A141119 A141120 A141121
|
|
|
KEYWORD
| sign
|
|
|
AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), Jun 05 2008
|
| |
|
|
