A218115 G.f.: A(x,y) = exp( Sum_{n>=1} [Sum_{k=0..n} C(n,k)^5 * y^k] * x^n/n ) = Sum_{n>=0,k=0..n} T(n,k)*x^n*y^k, as a triangle of coefficients T(n,k) read by rows.
1, 1, 1, 1, 17, 1, 1, 98, 98, 1, 1, 354, 2251, 354, 1, 1, 979, 23803, 23803, 979, 1, 1, 2275, 158367, 617036, 158367, 2275, 1, 1, 4676, 773842, 8763293, 8763293, 773842, 4676, 1, 1, 8772, 3031668, 82498785, 241082026, 82498785, 3031668, 8772, 1, 1, 15333
Offset: 0
Examples
G.f.: A(x,y) = 1 + (1+y)*x + (1+17*y+y^2)*x^2 + (1+98*y+98*y^2+y^3)*x^3 + (1+354*y+2251*y^2+354*y^3+y^4)*x^4 +... The logarithm of the g.f. equals the series: log(A(x,y)) = (1 + y)*x + (1 + 2^5*y + y^2)*x^2/2 + (1 + 3^5*y + 3^5*y^2 + y^3)*x^3/3 + (1 + 4^5*y + 6^5*y^2 + 4^5*y^3 + y^4)*x^4/4 + (1 + 5^5*y + 10^5*y^2 + 10^5*y^3 + 5^5*y^4 + y^5)*x^5/5 +... Triangle begins: 1; 1, 1; 1, 17, 1; 1, 98, 98, 1; 1, 354, 2251, 354, 1; 1, 979, 23803, 23803, 979, 1; 1, 2275, 158367, 617036, 158367, 2275, 1; 1, 4676, 773842, 8763293, 8763293, 773842, 4676, 1; 1, 8772, 3031668, 82498785, 241082026, 82498785, 3031668, 8772, 1; 1, 15333, 10057620, 575963523, 4066874561, 4066874561, 575963523, 10057620, 15333, 1; ... Note that column 1 forms the sum of fourth powers (A000538).
Crossrefs
Programs
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PARI
{T(n, k)=polcoeff(polcoeff(exp(sum(m=1, n, sum(j=0, m, binomial(m, j)^5*y^j)*x^m/m)+O(x^(n+1))), n, x), k, y)} for(n=0, 10, for(k=0, n, print1(T(n, k), ", ")); print(""))
Comments