OFFSET
0,3
REFERENCES
M. Domaratzki, A Generalization of the Genocchi Numbers with Applications to Enumeration of Finite Automata, Technical Report 2001-449, Department of Computing and Information Science, Queen's University of Kingston (Kingston, Canada).
LINKS
Michael Domaratzki, Combinatorial Interpretations of a Generalization of the Genocchi Numbers, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.6.
FORMULA
a(n) = A(n-1, 1) for the above Gandhi polynomials.
O.g.f.: Sum_{n>=0} n!^3 * x^n / Product_{k=1..n} (1 + k^3*x). [From Paul D. Hanna, Jul 21 2011]
EXAMPLE
O.g.f.: A(x) = 1 + x + 7*x^2 + 145*x^3 + 6631*x^4 + 566641*x^5 +...
where A(x) = 1 + x/(1+x) + 2!^3*x^2/((1+x)*(1+8*x)) + 3!^3*x^3/((1+x)*(1+8*x)*(1+27*x)) + 4!^3*x^4/((1+x)*(1+8*x)*(1+27*x)*(1+64*x)) +... [From Paul D. Hanna, Jul 21 2011]
MATHEMATICA
a[n_ /; n >= 0, r_ /; r >= 0] := a[n, r] = r^3*a[n-1, r+1] - (r-1)^3*a[n-1, r]; a[1, r_ /; r >= 0] := r^3-(r-1)^3; a[_, _] = 1; a[n_] := a[n-1, 1]; Table[a[n], {n, 0, 13}] (* Jean-François Alcover, May 23 2013 *)
PROG
(PARI) {a(n)=polcoeff(sum(m=0, n, m!^3*x^m/prod(k=1, m, 1+k^3*x+x*O(x^n))), n)}
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Mike Domaratzki (mdomaratzki(AT)alumni.uwaterloo.ca), Sep 28 2001
STATUS
approved