A229041 G.f. A(x) satisfies: [x^n] A(x)^(n^2-n+1) = 0 for n>=2.

1, 1, -1, 1, -7, -49, -1191, -31569, -1051695, -41520593, -1896894223, -98362962257, -5705059841823, -365846227736001, -25696840682622175, -1961769357361345473, -161728572333727674687, -14318505129615014956737, -1354916705432679538845759, -136467389971873491004759617

Offset

0,5

Comments

G.f. A(x) satisfies:

(1) A(x) = G(x*A(x)) where G(x) = A(x/G(x)) is the g.f. of A185072.

(2) A(x) = F(x/A(x)) where F(x) = A(x*F(x)) is the g.f. of A229044.

Links

Table of n, a(n) for n=0..19.

Example

G.f.: A(x) = 1 + x - x^2 + x^3 - 7*x^4 - 49*x^5 - 1191*x^6 - 31569*x^7 -...
Coefficients of x^k in the powers A(x)^(n^2-n+1) of g.f. A(x) begin:
n=1: [1, 1,  -1,    1,    -7,    -49,   -1191,   -31569,  -1051695, ...];
n=2: [1, 3,   0,   -2,   -15,   -189,   -3850,  -101700,  -3340845, ...];
n=3: [1, 7,  14,    0,   -56,   -588,  -10808,  -273972,  -8760325, ...];
n=4: [1,13,  65,  143,     0,  -1742,  -27534,  -638690, -19496334, ...];
n=5: [1,21, 189,  931,  2478,      0,  -67312, -1444608, -40653711, ...];
n=6: [1,31, 434, 3596, 19158,  62062,       0, -3116120, -84939504, ...];
n=7: [1,43, 860,10578, 88795, 526449, 2045854,        0,-167991196, ...];
n=8: [1,57,1539,26125,311619,2754297,18283187, 83718693,         0, ...];
...
where the coefficients of x^n in A(x)^(n^2-n+1) all equal zero for n>=2.

Prog

(PARI) {a(n)=local(A=[1, 1]); for(k=1, n, A=concat(A, 0); A[#A]=-polcoeff((Ser(A) +O(x^(k+2)))^(k^2+k+1)/(k^2+k+1), k+1)); A[n+1]}
for(n=0, 30, print1(a(n), ", "))

Crossrefs

Cf. A185072, A229044, A230218, A171791.

Sequence in context: A135745 A080895 A047899 * A263247 A259990 A061585

Adjacent sequences: A229038 A229039 A229040 * A229042 A229043 A229044

Keyword

sign

Author

Paul D. Hanna, Sep 14 2013

Status

approved