A208833 G.f.: 1+x = Sum_{n>=0} a(n) * x^n * Product_{k=1..n} (1 - k*x)/(1 + k*x).

1, 1, 2, 10, 86, 1082, 18202, 386834, 9990206, 304821826, 10757265314, 431846459786, 19460311559446, 973722006221210, 53610324625950938, 3223029995174243506, 210202324733850002846, 14787932100812573072642, 1116673488757504695366658, 90116245915518156986943818

Offset

0,3

Links

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

Example

 G.f.: 1+x = 1 + 1*x*(1-x)/(1+x) + 2*x^2*(1-x)*(1-2*x)/((1+x)*(1+2*x)) + 10*x^3*(1-x)*(1-2*x)*(1-3*x)/((1+x)*(1+2*x)*(1+3*x)) + 86*x^4*(1-x)*(1-2*x)*(1-3*x)*(1-4*x)/((1+x)*(1+2*x)*(1+3*x)*(1+4*x)) +...

Prog

 (PARI) {a(n)=if(n==0, 1, polcoeff(1+x-sum(k=0, n-1, a(k)*x^k*prod(j=1, k, (1-j*x)/(1+j*x+x*O(x^n)))), n))}
for(n=0, 25, print1(a(n), ", "))

Crossrefs

Cf. A208832.

Sequence in context: A367372 A372177 A371005 * A145082 A335501 A355083

Adjacent sequences: A208830 A208831 A208832 * A208834 A208835 A208836

Keyword

nonn

Author

Paul D. Hanna, Mar 01 2012

Status

approved