|
|
A294161
|
|
Column 1 of triangle A291844.
|
|
6
|
|
|
2, 23, 292, 4068, 62861, 1075562, 20275944, 418724047, 9418874022, 229535650138, 6029910590473, 169978358728536, 5120224516689050, 164192864744507615, 5585978669387706724, 200988595873323113508, 7626780547253339197109, 304431018444668653351250, 12752396616363975496913952, 559388848572350998030227895
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
2,1
|
|
LINKS
|
|
|
PROG
|
(PARI)
my(x='x+O('x^N), y=1, y1=0, n=1,
dn = 1/(-2*t^2*x^4 - (2*t^2+3*t)*x^3 - (2*t+1)*x^2 + (2*t-1)*x + 1));
while (n++,
y1 = (2*x^2*y'*((-t^2 + t)*x + (-t + 1) + (t^2*x^2 + (t^2 + t)*x + t)*y) +
(t*x^2 + t*x)*y^2 - (2*t^2*x^3 + 3*t*x^2 + (-t + 1)*x - 1))*dn;
if (y1 == y, break); y = y1; ); y;
};
((1+x)*z - 1)*(1 + t*x)/((1-t + t*(1+x)*z)*x*z^2);
};
my(s = A291844_ser(N+1+3*k\2, t='t + O('t^(k+1))));
Ser(polcoeff(s, k, 't), 'x, N);
};
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|