|
| |
|
|
A122992
|
|
G.f.: A(x) = Product_{n>=0} ( 1 + x*(1+x)^n )^( 1/2^(n+1) ).
|
|
1
| |
|
|
1, 1, 1, 1, 0, -2, -5, -3, 27, 145, 382, -24, -6796, -44972, -167234, -105302, 4182671, 41042943, 232150003, 618910867, -4104725087, -76739338173, -670022786184, -3614373261686, -3033843119112, 208905541624840, 3094995814651910, 27593428414596086
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,6
|
|
|
EXAMPLE
| A(x) = (1+x)^(1/2) * (1 + x*(1+x))^(1/4) * (1 + x*(1+x)^2)^(1/8) * (1 + x*(1+x)^3)^(1/16) * ...
|
|
|
PROG
| (PARI) {a(n)=round(polcoeff(prod(i=0, 6*n+10, (1+x*(1+x)^i +x*O(x^n))^(1/2^(i+1))), n))}
(PARI) {a(n)=local(A); if(n<0, 0, A=1+O(x); for(k=1, n, A=truncate(A)+x*O(x^k); A+=substvec(A, [x, y], [x*(1+x*y), y/(1+x*y+O(x^k))]) -A^2/(1+x)); subst(polcoeff(A, n), y, 1))} /* Michael Somos Oct 21 2006 */
|
|
|
CROSSREFS
| Cf. A122993.
Sequence in context: A058357 A176613 A097754 * A051497 A109734 A077073
Adjacent sequences: A122989 A122990 A122991 * A122993 A122994 A122995
|
|
|
KEYWORD
| sign
|
|
|
AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), Sep 23 2006
|
| |
|
|
