189224

Appears in sequences

• Consider the family of multigraphs enriched by the species of cycles. Sequence gives the triangle read by rows giving coefficients of polynomials arising from enumeration of those multigraphs on n edges.at n=41A098283
• G.f. x*(x^2+1)*(x^3-x-1)/((2*x^3+x^2-1)*(x^4+1)).at n=31A107854
• a(n) = (n-1)*(n+2)*(n^2 + n + 2)/4.at n=28A168566
• Numbers k such that k and k+1 are both half-Zumkeller numbers (A246198).at n=20A331371